Hi everyone...this is my first post on the board, but I'm really glad to be on here and finally connecting with other people in similar situations.  Any advice or suggestions would be hugely appreciated!!

I'm a mom to a really amazing 15 year old boy who I had when I was a senior in high school.  I'm 34 now and was in a relationship with my son's father/ex husband for a total of 16 years (married for 12).  He was 100% who I wanted to be with for the rest of my life and I was head over heels in love with him from day one.  We oddly enough never really had that great of a relationship, but it worked for us and at the end of the day we both loved each other very much.  Long story short, I found out he had been cheating on me for 10 of the 12 years we were married and then developed an alcohol and prescription drug addiction.  I tried as hard as I could for as long as I could, but he was spirialing out of control fast and it was no longer safe for DS and I to stay so I made an extremely difficult decision and left.  We moved back in with my parents and have been here for the past two years until my divorce was finalized which just happened in June and now I'm waiting to receive the settlement so we can move into our own home.  I have always been a stay at home mom which is great and I feel very fortunate to have been able to afford that, but also see now how important it is to have a degree/career to fall back on if needed.

Going back a little bit, a few months after my ex husband and I separated I started a relationship with someone else and he and I have been attached at the hip since.  We have such an amazing time together, he's extremely patient and kind and treats me better every single day which I didn't even think was possible.  Thing is that he has three kids (DS 12, DS 9 and DD 7) and is still legally married to an absolutely bitter resentful and miserable woman.  I don't and never have liked kids.  I love my own son more than anything in the entire world, but that's different because he's mine and he and I have always been a team.  I have zero connection with these kids and I honestly don't really want to develop one.  It's of no fault of the kids, but they're all developmentally behind, badly behaved and leave huge messes everywhere.  The oldest boy leaves food and chewed gum all over the place and is completely addicted to electronics.  The middle boy is sweet, but loves to stir the pot and the girl is just whiny and pitches fits until she gets what she wants.  To my SO's credit, he doesn't put up with or tolerate any of that and it doesn't fly in his presence, BUT they're with their mom 90% of the time and she allows them to get away with the behavior and doesn't work with them on developmental skills even though she's dual certified in regular education as well as special education.  She's lazy and refuses to work professionally or as a parent so that makes it like you're starting back at square one every other weekend when SO gets them.  

If he's scheduled to get the kids for the weekend I'm a total jackass all week and deliberately pick fights so I won't feel obligated to be around when he has them.  It's really starting to put a strain on our relationship and I do love him and would like to be with him, but I also realize his kids are a part of his life and I need to be accepting of them also if this is going to work.  He and his soon to be ex wife also don't speak at all.  He absolutely despises her and wants no part of her so while it's nice in some ways, it also makes things more difficult at times.  Admittedly because of being cheated on for over a decade my self confidence and willingness to trust other people is lacking significantly.  I realize I'm stubborn and difficult and don't necessarily handle not getting my way as well as I should for being a 34 year old mother; however, I feel like I've settled for so long that I don't want to be in a relationship again that's going to be an uphill battle all the time.  I understand all relationships take work, but my dislike for my SO's kids is just so strong that I feel like it's doomed to fail.  

Last thing that I think is pretty relevant here is that after we first got together I found out I was pregnant.  My ex husband had a vasectomy so I wasn't use to having to worry about birth control and SO's soon to be ex had an IUD put in after she deliberately got pregnant with DD behind his back after saying she was on BC, but wasn't taking it.  Urgh... He really didn't want the third child and actually pushed for her to be aborted as awful as that sounds.  He knew their relationship was bad and wasn't really ever good even from the beginning so more kids wasn't on his radar.  She on the other hand has always used the kids as a means to not work.  That's a separate issue though.  Anyway, because we had been together for such a short time and weren't even public with our relationship, I decided to abort the baby which as hard as it was to do was definitely the right decision for the time.  As much as I don't like kids and never wanted to have more of them I think I was so head over heels for this person and felt so great finally feeling like I was the center of someone's world, I got the ingenious idea that maybe I wanted a child with SO.  Thinking about it now I realize it was more that because of my insecurities I just desperately wanted a connection with him through a baby since he had that with someone else.  Stupid I know and I firmly believe babies should not be born with jobs or as a means to create some forever attachment for personal gain. 

That being said, he decided he wanted a baby with me because of how strongly he felt about me so while we weren't trying to get pregnant we weren't really doing much to prevent it either.  I ended up getting pregnant again in July 2017, but miscarried in September and we both took that really hard.  I got pregnant again in October but again miscarried in December right before Christmas.  That was pretty much devastating and put a huge dent in everything.  I've now decided kids aren't meant to be for me and I'm good with that.  I'm not at a point in my life where I want to be responsible for little tiny people again so I believe all this happened for a reason.  It still doesn't make it any easier though and now when I see his kids I see these three little people he created with someone else and I think about the three little babies we created and how none of them ever made it into our world.  It seriously breaks my heart.

SO spends a ton of time with my DS because I have my DS 100% of the time due to my ex's addiction issues.  SO is beyond wonderful with him which is great, but also makes me feel even more like an ass because of how I am with his kids when we hardly ever even see them.  The whole thing just sucks.  We're at the point where I feel like I'm just not willing to give at all and he's been giving so much he doesn't feel like he can give anymore without cutting his kids totally out of his life.  If his kids were even older maybe it wouldn't be so bad, but they're just so young still... I don't know what to do.  I love him and he's honestly perfect in every way except the fact that he has the kids.  Do I cut my losses and stop the constant drama for everyone and walk away or do I suck it up and work harder to be more accepting?  His kids aren't ever disrespectful to me and he would never allow them to be that way.  I really feel like I'm just pissed he has three kids with someone else especially when he says he knew marrying her that it was wrong and never truly loved her, but felt like he was getting to the age where he needed to get married if he was going to have kids and always wanted to have two.  Because I don't like kids I guess I take having them and having them with the right person a little more seriously, but who am I to judge?  I didn't exactly get it right either...

Help!!  I'm driving myself (and everyone else) totally nuts :-(  Hopefully all this made sense...I know I threw a lot out there, lol