Many on this site would get down on their knees and give thanks that their DH was handling the grown SKs outside the home.  I understand why you were upset about the trip last year when you were sick.  This year, I'm not understanding but I see you are using the name Lonely so I'm guessing that's why.

I would look on this as an opportunity to have some "me" time.  Give yourself a facial, get a massage, whatever.  I think you might guide your child to not expect recognition from the SKs on birthdays, holidays.  They are young adults living their own lives and probably seldom give her a thought.  I was 8 years older than my siblings and was way too busy with my own life.

You seem to be aiming for the "blended" family model but it isn't working and I'd accept that.  If he visits them once a year, so what.  I'd focus on him and your daughter and let him handle them.  I doubt the dynamics will change at this point.

My favorite quote: " Mental health is an ongoing dedication to reality at all costs.  Good luck.

Great advice from JRI.

Similar situation here. I focus on my life with my two sons and DH. His adult daughter and her family are in another state and he goes to visit once a year. Our lives are separate. I have no interest in being involved (she has been a long-time addict but seems to be doing better right now). I like to keep the drama at a distance. I enjoy my peaceful life and surround myself with my friends and family. 

She is getting to the age where she notices her half sisters from her dad's side don't call her or remember her birthday and don't get her a Christmas present or call or anything. It hurts her.

It does hurt to see your child feeling slighted and forgotten.

I get it.  

You are lonely because he has another woman in his life, that woman is his adult daughter. Secretive or last minute mentioning of plans, he chooses moving her over a wife with Covid. If you take out daughter and asked people to insert another word, that word may very well be mistress. Doesnt feel good does it? I had that in my marriage with ex DH. His mini wife DD was the wife, and more like I was the mistress. Except not the exotic mistress, the type of mistress that scrubbed toilets and washed his clothes.

The above advice is great but I totally get how you feel, LONELY. Also your 13 yr old DD also feels left out because of the half siblings. I can only imagine the long term sadness she may have.

Other than disengaging and keeping yourself busy like above have mentioned I really have no good advice. Your DH sounds wrapped up in his adult DD and NOTHING not even covid can foil those plans. Speaking of that DANG. No wonder our US of A is where its at today. He went travelling knowing he was positive. He could have passed it on to his DD and all the people he had contact with along the way SMH!

The best you can do is have a conversation of your expectations as his WIFE. Other than that, IDK.

Blessings

Your DH sounds selfish. He tested positive for COVID, didn't tell you, and still went on a roadtrip? It's good his symptoms weren't bad, but he could have spread that virus to others who DID suffer or, worse, die. This type of behavior is one reason why we continue to be in a pandemic. Selfishness.

You and SD don't have to like each other -- you're both adults and you get to pick your own friends. To her, you are just "Dad's wife." And that's fine. Your issue is really with your DH and his lack of communication and his keeping secrets about his plans. Secret relationships are the death of marriages, whether it is an actual affair or just feels like one.

There's got to be a better balance. You aren't saying he can't see his kids. You are just saying you'd like to be part of any decisions and plans that affect you--and his traveling certainly does. You, the wife, should be his primary relationship and he's not treating it as such.

The world does not revolve around him and his kids, despite the way he's acting. If he won't talk through this with you, and I doubt he'd agree to see a marriage counselor, see a counselor for yourself. A therapist will help you work through your hurt and put some boundaries around what you need to feel happy and healthy.

I got stuck at "Even though he was tested (and confirmed positive though he didn't tell me) he kept his plans to help her as his only symptoms was loss of smell." 
He drove across numerous states while Covid positive exposing everyone he met. His attitude is one of the reasons we, as a society, can't get this under control.

This dude likely spread COVID around multiple states. I bet he's one of those who is like "I didn't have symptoms, so i don't know what everyone's complaining about." It's the same selfishness that leads these biodads (and moms) to be like "The situation doesn't bother *me*, so why change anything?" It's a character flaw and leads to discord in every area of their lives. 

You gave us the bare bones of 20 years and none of it sounds good. Im sure that there was good in there, but what you described is a very selfish, self-centered man who prioritises his daughter over his wife and has excluded you and put you and your feelings to the side your entire relationship.

SO. While you mull things over, read posts on here, look up the term narcissistic and mini-wife, guilty parent, please make an appointment with a lawyer to see what your life would look like without him. Just to see what your options would be. Its never too late to start fresh. And you have your bio to look out for, who has gotten used to being low on the priority totem pole.

You dont mention working. If you dont have one, get a job now. Focus on your kiddo. Focus on yourself, because your partner DOES NOT HAVE YOUR BACK. Youve had 20 years to see who he is, he has shown you. And hes helped spread the virus to many many people, probably caused some hospitalizations and deaths. He has SHOWN YOU WHO HE IS - a person lacking in good character who doesnt have the same values that you do.

Make that consultation appointment today. 

My guess is he scheduled it for a time he knew darn well you two couldn't go.  Just like he left you home sick with a disease that has killed 612K in the U.S. alone.  Many people died after initial onset over a few days.  Apparently he wasn't even concerned his own child would be left alone should you have passed. Hell, he was so engrossed in his older daughter that he exposed her, the one he loves so much, and the public at large, to COVID-19.  I think your intuition is right, your marriage is in serious trouble.  Jeeze, It doesn't sound like he bothers with his other adult kid/kids either, just obsesses over the one.  You're describing a kind of psychological incest.  Now, weather it is conscious or subconscious only he can answer that.  People have recommended some great things.  Counseling for yourself is a great way to start.  Making friends away from your husband would help you a lot also, maybe with a lady with a pre-teen girl too so you have things in common.  Save up money of your own just in case you decide to leave.  Just take it one step at a time until you make a decision.  Please, if you haven't gotten your 13 y.o. vaccinated yet, make it your first priority.  The Pfizer COVID-19 vaccine has been approved for kids aged 12-15.  I can relate some as I have a similar issue with my bf and his 24yo son, who he is sickeningly codependent on his son.  

Your DH is not only a shitty father to his prior failed family progeny, he is a shitty father to your daughter as well. Not to mention a shitty husband. Your adult Skids have had their turn to have him be their father when they were 13.  It is now your daughter's turn to have her dad around and fortunately she has you to put your foot up his idiot ass. So... apply foot to idiot ass.  You need to crush him repeatedly with the heart break and bullshit he is perpetrating against your young daughter and against you and your marriage.

Time to give him clarity that this ends now. No more adult kid ass sucking worship fest trips or visits with them. From now on, you and your young teen daughter go. And... immediatly he starts taking his "family" of the three of you only vacations.  Your Skids are adults. His daughter with you is not.

Your DH... is just a dick. Not to mention a complete and total dumb ass.

Grrrrr. This guy pisses me off.

Ooops!

"make it up to them" until his last breath. It's apparent in his "help" with the move to CA, her photos on his phone lock screen and his trip to CA without you or your daughter. 

Most of these daddies compartmentalize relationships. In the beginning they don't, but one thing we women eventually realize is we don't have a SK problem, we have a DH PROBLEM.  Mine is the architect of his own hell. Though I absolutely adored him (despite the fact he is much older than me, no sex, no financial security and more...I overlooked a lot and catered to his every whim) he would talk negatively about me to them, which of course changed our entire dynamic.They bond over their dysfunction. Doing things for them or with them is their way of showing them their undying love to SKs. 

As for him not telling you, or sharing with you that he plans to make another trip, this is a playbook they all read from. These "men" do this because they don't want to hear anything from us about it. They CHOOSE to take the path of least resistance because that is what works best for THEM. It's actually VERY SELFISH. The least he/they (DHs) could do is tell us in advance so WE CAN MAKE PLANS to do whatever brings US JOY.

If your DH doesn't "get it" it's because he doesn't want to. I mean, to admit things need to change is self admission that he's a failure as a parent to his first brood. Nothing will change on his behalf where change is not desired, sadly.

I'm sorry you're having to deal with this mess. I really feel badly for you and your 13 year old daughter you share with him.

What utter tosh! He was "hurting" because his wife would like him to reprogram a long-distance trip so that she and their daughter can go with him? What kind of crap is that?