First of all, I'm so sorry for the loss of your little baby boy.  How sad that is.

You're not evil, you sound very insightful.  Step-parenting is such a weird dynamic, we are suddernly thrust into a parental role with strangers.  

As you described your SD, she reminded me of myself as a child.  I also was/am unathletic, kind of lazy -my poor stepdad probably thought the same as you.  Altho I took several years of swimming lessons as a child and more as an adult, I still can't swim.

You're right that all you really have to do is provide a safe environment.  My DH, too, strongly encourages a relationship with my SD with whom I have a conflicted dynamic.  I take it as a compliment from him but it's tough.

One thing to keep in mind is that no matter what you think, your DD is the half-sister of your SD.  It's in your and her best interest to foster a positive relationship.  In years to come, the 2 of them might figuring out DH's care as an aged person. 

Best of luck, step-parenting is hard, especially if the child is so different from us.

Firstly, I am so sorry for your loss. And congratulations on your impending bundle of joy.

You sound practical and have systematically described the things about your very young SD that you dont like, adding to the fact you do not care for her.

Society is programmed to tell parents "Steppers must love their partners child like they would love their own."

False. You absolutely are not required to "love them like your own". You dont have that DNA shared. You did not make them. You are not parenting them. You can TREAT them as you would your own child. Theres a big difference.

So, now to the elephant in the room. Why, if your partner was such a lousy father to your SD11 (he shares responsibility!) would you:

a. want to stick around to watch the sh!t show of SD11 growing up and

b. Why do you think he would do such a great job with YOUR children together? A do-over because he realized he failed so badly the first time? Will you be happy doing all the parenting????

Please give me a little insight. No judgement, just putting that out there...

I think your emotions are probably extra strong right now because of the pregnancy. A weird thing happened to me when i was pregnant with my first - i sort of had a revulsion to kids i wasn't related to. Felt like they were germy and were a threat to my unborn child. It had to be the hormones because i wasn't like that before or after. Mix that in with the whole stepkid dynamic of being made to feel you *should* feel and act a certain way (love them like your own even though you can't control jack shite about their upbringing), and also a babymamma you find revolting  always skulking around in the background of your life. Yeah. What you feel is probably normal. What you need to do, however, is treat SD with kindness and respect, and exercise common decency. You aren't required to do the heavy lifting of parenting, and anyone who tells you you are can fk off. But if she gets hurt, help her, etc. 

So many emotions that you have. I am so sorry that you are so miserable, but I appreciate your honesty.Your hormones may have something to do with your writing, but you sound so very depressed. I also am sorry for the loss of your son. Congratulations on the upcoming birth of your daughter. You said you have no one else to talk to, but this forum. Please find someone, online therapy, a pastor, a friend to talk to, to get instant feedback. Your SD is 12? 6  years will fly by, seriously, I know. She may need you at some point in her life, don't close that door (my step did after 35 years, but this is your post). Hang in there. This will pass. Prayers.

Practically word for word I could have wrote this besides the morbidly obese part.

I'm 29 with SD11, with her dad for 3 years now and every word you said I can perfectly relate to. I absolutely love your honesty and I feel the same exact way towards my SD11. The worst part is admitting I don't love her. I just don't. I tolerate her and I'm kind to her when she's in my home and makes sure she has the necessities but I do not care for her in a deep way whatsoever.

If you ever want to DM me, I feel like we would have a lot to talk about!

Sending you love and hugs for all you have been through and are going through!

boy.

You are not evil.  And though an 11yo should not be evil, your SD is by all indicators... evil.

Your plan to insulate your baby girl from the evil failed family progeny of your DH and is poor choice in prior breeding partners is the right one IMHO.  Do not question yourself on this and do not punish yourself for the perspective on your SD-11 that she and her parents have earned.

I do not have my own experience that parallels the loss you have experienced, I did watch my mom and dad go through it.  We lost my youngest brother when I was 9yo.  He passed at 9mos old from spinal meningitis.

He would be 51 this year.  My youngest nephew was born on my baby brother's birthday. That day is one of celebration for all of us but it is also a day where mom, dad and take some time to smile and remember their youngest. My surviving brother was only 2yo when the baby was born and has no memory of him.

Love your daughter, love and remember your son, and protect yourself and your family from the tragedy that your SD-11 represents.

Take care of  you.

I don't think you're evil.  You don't have to love your SD - just treat her with kindness and respect. Not my kid, not my problem is an acceptable position for a stepparent to take.  I can tell you that my interest in my SDs dropped when my own daughter was born - I don't think that's uncommon. .

I do think your "picker" for men is suspect, because your husband sounds like a real loser to me. He has failed his child miserably and doesn't appear to be doing anything to help her. How do you love and respect a man like that? How do you pick a man like that to be the father of your child?

But she needs more than a nutritionist. There is something much, much deeper here. Overeating and poor nutritional habits are just symptoms. She needs help with the root cause.

How do you think she's going to be successful in a sports camp when she is out of shape and not interested in sports? That sounds like an exercise (no pun intended) in public humiliation. 

If BM is a cr@p parent, and DH is a cr@p parent, is there an aunt or grandparent she's close to that can help?

First off I am so sorry for the loss of your baby. I cannot image. I am bio less so my following comments are in my opinion. I do not have the experience of a bio.

I totally feel empathy for SD.

I get your feelings of her, I really do.

BUT the poor kid will "feel" how little interest you have in her, and how you are disgusted by her. Yes she will feel that from her parents, but she will also notice that your bio will get the love and attention she craves. Since the love isnt there pizzas, donuts, you name it will be used to try and "fill" her. She definitely needs a therapist who cares.

 She will see and feel the favortism towards your bio. I am sure your bio will tow the line. Who knows because of the signals you send  your bio may do the opposite and become anorexic trying to please her perfectionist mama.

Im empathizing with you, or I really am trying. I also believe a SM cannot love the skids more than the parents. My sadness is this SD is already seen as a lost cause, at 12! I sure hope someone steps up for this girl.

Blessings and hope you are successful in navigating this step life to the best of your ability.

For the loss of your baby, I can't imagine what you've been through.

At first I was going to ask why you would want to be with a man who doesn't care about his child? But having read down there must be at least some element of care and concern as you've both taken steps to try and rectify sds weight. 

I can totally sympathise with the level of disgust such situations bring. My ss is also obese, and when we do go swimming or he's busy throwing up on a train I practically want to scream 'he's not mine' 

If your dh has tried what he can and you have rules in your house regarding eating , disengaging is all you can do if bm shows no concern 

I'm sorry for the loss of your baby and you congratulations on your new expecting bubs. 
I am also pregnant with my second and already have a DD2. 
I think you are definitely not evil but most likely hormonal and thanks to those hormones your tolerance is at a low. I can relate. 
I have empathy for your SD. She sounds lost and in deeperate need of a child psychologist. The waiting lists here at the moment for one is ridiculous- up to 6-12 months. My SS nearly 11 and SD9 haven't been to the dentist either. My DH is slack when it comes to following up on his own teeth let alone his children. BM - don't get me started. I think we all have similar issues when it comes to the skids hygiene that isn't up to our standards. 

I just wanted to say try not to compare your child to her half sister. When I was pregnant with DD I had the same thoughts like 'oh my child won't do what SD does' kind of thing. It was naive of me as I ended up having a beautiful angelic looking little girl but her personality is a damn strong one. She is 2 going on 15 sometimes as she is a sassy little thing. I seriously cannot believe she is 2. She speaks fluently and has real conversations and I am actually thankful for SD and SS being so patient with her as she demands them to play with her all the time and tries to boss them around.
But, she loves them so much.. all she does is talk about them when they are at BMs. Your baby might be like that too towards SD so try to keep the relationship with them positive. 

I hope when the baby is born your SD will change her tune and warm up to your little girl. Her comments about the death of your baby is a blow and definitely not ok. I think your DH needs to step up and nip that in the bud alot and it sounds like you will be a good mother so he can definitely learn a thing or too from you anyway. 

If you keep a positive outlook it does help. I was a bit over protective of DD as a baby when it came to SD by not allowing her to be in her room, and not pick her up, ect. but now I feel it's SD that needs protecting lol.. DD is more than capable of looking after herself which is definitely my personality. SD I think doesn't know how to handle her when DD pulls her up on things and I have to step in as a parent and correct DD. I wish you all the best in the next chapter when your baby comes. 

to consider her as you do.  She is not evil either, though both of her parents should be in prison.
IMHO.

Thousands of years of evolution has made babies cute, so the parents will love them and want to protect them, even when they are annoying. Erikson termed this cuteness 'baby-esque': big head, big eyes, button noses, cute smiles, enables bonding.

SPs have no memory of when their skids were cute babies, and some of theses skids are not cute adolescents. It makes it harder to bond with them, for sure. Add in personality incompatibility (I am the opposite of basic, and my SD is vapid AF), makes it even harder to gel.

Then you experienced a tragedy, and your SD said something really really insensistive. It may be hard to come back from that. Maybe when you get over mourning, you will forgive her, maybe not.

My SD did something unforgiveable, and I tried to forgive her but I couldn't. I just never will, and I forgive myself for that.

Be gentle with yourself. If you really don't want to do something, give yourself permission to say No.

I got to a point where I literally couldn't be around my SD. She has an evil BM like yours does, and it really messed her up, which is sad, but I can't fix it, and really, it's not my responsibility. I did try, but nothing I did helped.

However...

It's not her fault she is the way she is, and I never wanted to hurt her more or damage her self esteem. DH had full custody, so she was here every day. I avoided her, and I'm sure she felt shunned, but that wasn't intentional. But no child should feel shunned or hated in their own home, which I why I kicked her and DH out. She can go be crazy somewhere else. It took me years to get over my rage.

I think if you are emanating hatred for this child it would be best to just avoid her as much as possible. Your DH doesn't have custody. Maybe time and distance will heal some of the hurt.