There is and adult step kid board and I suggest you spend some time there reading. You aren't alone in having defective stepdaughters that have their own lives.  I think you're right keeping them distant. I wonder, have you told the SDs exactly why they get treated the way they do by you?   Daddy might pussyfoot around the truth but do you?  

Honestly, the 30 year old doesn't sound nearly as bad as you paint her to be. There is some goose and gandering going on it seems. It's totally reasonable for her not to include you on her wedding invitations because you aren't her parent. Being distant with you shouldn't negate invitations into her father's home similar to what is allowed for your own children if she is polite and civil to you. Having pictures with her parents, even if divorced, is a pretty standard photo request at a wedding.

I'm going to assume there is more, because honestly, what you've written about the 30 year old DOES sound like she gets treated worse than your own kids because she doesn't act like your kids, but that doesn't make her bad so much as just make her different. She may have some very good reasons for her personally that she doesn't want to (or can't be) closer to you, and those reasons shouldn't prevent her from seeing her father in his home (in a home that likely feels like a family home to her just as it does to your kids).

Now, YOU don't need to be the one hosting her on weekends. That needs to be your DH. If he is expecting you to reach out with invitations and make up the house for her, then the problem is less SD and more DH. He needs to be doing these things and letting her blame you isn't fair. There's no "to his credit" on that. Him letting SD think you're the gatekeeper keeping her away because he's too lazy to host his own daughter is bullsh*t and needs to land squarely back in his lap every time it happens.

The 33YO sounds problematic. BPD isn't something you should have in your life. Can't blame you one bit for keeping that out. My SSis has BPD (according to her, anyway), and the further away she is from me, the better.

Lastly, you may want to re-examine your visitor policy. Antibodies doesn't mean unable to spread COVID. With new variants around, it's entirely possible for someone who has been previously infected to spread COVID, especially asymptomatically. Plus, antibody protection wanes in folks, and it's impossible to know if someone is still protected or not. Repeat infection with the same strain is rare, but not getting sick yourself doesn't mean you can't carry it to others. The same applies with the vaccine, which the primary function of the vaccine is to cause an immune response faster so you don't get sick OR you don't get sick as quickly. That doesn't mean you don't carry virus around with you, though. Don't take antibodies and vaccines as carte blanche permission to interact with folks like you're protected. They might be, but that doesn't mean you are.

I don't have any advice for you but a lot of empathy.  I have two SDs aged 26 and 24 who sound similar to yours.  SD26 is in process of being diagnosed as bipolar, their mother is NPD and I suspect both SDs are too.   I have never really had a relationship with them, because of her, despite the fact I came into their lives when they were 5 and 7. They have both always been jealous of my bios (both in 30s) and my grandchildren.   Like you, I am early 60s, by which age one might be hoping for a bit of peace - no chance!  Issues with the SDs have come close to splitting me and my DH up numerous times in the last few years - they are the ONLY thing we ever argue about.  

I'll admit that I don't really understand why your 2nd SD is jealous of your relationship with your own kids and grandkids. It seems to me that she's directing her discontent at the wrong person. If she wants to be invited more often to your place, shouldn't her father be the one doing the inviting? About staying at your place for weekends  - how far away do your children live and how far away does she live?

Another "good man" who lets his kids mistreat his wife because they are "damaged" by BM, instead of setting limits.  BM is not the only one who has damaged them with poor parenting.  7 years he allowed his daughter to treat you poorly and it would still be going on now if you hadn't done something about it. 

I too am a bit more confused about the younger one. She doesn't sound too bad. 

Yet another example with shitty SD's. They will look for anything to have fault in you, even the "nicer" younger SD. If it isnt you favor your family, it will be Christmas gifts, birthdays, any occassion to find fault with you.

It is her right to feel anyway about you, as it is YOUR right to respond how she treats you. Its your home and you can decide what perameters you set regarding Covid and invites. The mere fact that she mingles with others on a regular basis to not allow her in your home is your choice.

Does the younger SD treat you the same as her mother? NFW she does, so why in the hell should you treat her the same as the bios. These SD feel "uncomfortable" because the witch bitch SM do not treat them like their own YET it is Ok for her to treat you poorly. The permanent victim arent they? Double standards and stephole seems to be the way these skids want it to play out.

Your DH doesnt back you up. Well F that, then you go rogue on these bitches. If your DH gets mad you tell him that since you cannot rely on him to keep them in check you resorted to taking care of yourself.

Dang it, I hate how these SD's are life suckers, taking joy out of our lives because THEY are miserable.

I'm glad you replied and explained more about your situation.  Sounds to me that DH is the one making you miserable.  If all of this is coming directly from him, then you need to shut him down.  He's the one talking to you , not her.  
 

When there are small kids involved, the stepparent is often recommended to put it to the lazy parent this way: either you take care of it or I will and you won't like the way I do it.  I think the same philosophy needs to be applied here.  Either he sets her straight about things or you will do it.  It sounds like she is blindly jealous of a parental relationship she does not have with either of her parents.   She is in a way projecting that on to you instead of on her father.  A triangle of drama.   Take yourself out of the triangle and let the two of them figure it out or not.  Do shut your husband down.  You don't deserve his badgering about HIS problem.    IMO 
 

Even if your adult children have the antibodies they can still carry COVID, I think.

My SD is also terribly jealous of anyone her father pays attention to. That includes me, my bios and even her own brother.

I made it VERY clear to my DH that he is responsible for the relationship with his kids. I'll be responsible for my kids. SD and I are polite, cordial, sometimes even friendly. But I have nothing to do with planning activities with his kids -- that's all on him. We live far enough away that visits are infrequent and require overnights (none since COVID), and I am happy for his kids and mine to come. But HE is responsible for activities, meals, groceries, etc. for his kids. 

If SD ever complained about me and what I provide for my kids, I wouldn't want to hear it. None of her business, and DH can just deal with it or listen to her gripe. I don't think she does much of that, but I would ignore it and it certainly wouldn't be my problem to solve or burden to carry.