Hi Stepcrazy2, I see no one has replied to your post, so I will give some thoughts.....

I am really trying hard to put myself in your shoes, as I have been a stepmother twice and as all will tell you on this site, it is the worst role you as a person will ever have. But surely you knew your DH had kids before you married him?

It will be crazy with the age gap between bio & step kids, but somehow you will have to put structures in place to deal with it. You could disengage if it is really driving you too crazy, or plan outings for u (within walking distance, as u say u don't have a car)& BS21 when the kids are around, just to get some peace. Make FH realise how much pressure you are under with the skids and make him step up as a parent.

You don't say why BS21 is still at home, but I am guessing he is either studying or out of a job also. Make finding a job a priority, even if it is community oriented or voluntary to start off with, just to make yourself feel of more worth. Who knows, it may grow to something more substantial later.

I feel for you. You must really have loved DH to get yourself into this situation.

All the best to u!

Welcome! You have come to the right place. Steptalk is a really good start to getting some support in terms of being able to vent and share your thoughts. I really don't know the particulars of your situation but I have a 22 yr daughter and two stepdaughters (11 & 6) and it's a difficult transition, because you have already been through it all and NOW YOU have to go through it all over again, plus YOU have to deal with the dynamtics of a BM relationship, etc. It's terrifing and frankly I almost ran away on several occassions after weekends with skids. I went from being single to being a mom and I felt like I was being taken advantage of.
However, for me I am a communicator...I read, I process, I talk, I read, I write, I talk, I process...etc. etc. etc. I am very very lucky, my fiancee listens and he tries to see my side.
Recently, skids were here for a week and mid way through the week they started complaining, and demanding more and more of my time and engery. I have a bad knee and it's difficult for me to go up and downstairs a few times let alone 100+ times. That is what was happening...I was cleaning after skids every 1/2 hour, running up and down the stairs for every "I need this, I need that!!", I was making lunch, then a snack, then they are hungry again, then something to drink, then something else to eat, more dishes, more cleaning...get the picture!!!! It was horrible, my knee was swollen, my back ached, my hip was throbbing and I am holding a broom sweeping the floor (AGAIN!!!) and my little stepdaughters start complaining about how they hate it here, they want to go home, they want mom, why is daddy working so much, etc. etc. etc. I was in such pain I couldn't take the whinning (usually I can tolerate a lot) but to me all the whinning and complaining was the last straw that broke MY back!!! (seriously, I was not able to walk the next day, could not get out of bed!!!)
I said to skids...
"I want my mom too!!!" I rather be there than here right now after all these comments and lack of respect toward me and your father!"
"do you realize that I don't need to be here?!?!"
"do you realize that you could be at camp or at your mothers, or anyway but here?!?!"
"do you realize that if I wasn't here your father who loves you very much would not be able to see you as much as he does because he works 6 days a week, gets one day a month to himself, meaning you aren't around and he doesn't have to work...do you realize that?!?!
"Do you realize why he works so much, to put food, a roof and clothes on his kids (YOU!!!) when you are at your moms, and also when you are here?!?!"
Do you realize I am VOLUNTEERING to be here with you, because I love your father and I also love you, but you are making it very difficult to love you when you act this way and say the things you say?!?!?"
"have you realized how much weight your father has lost?!?! that is due to the level of stress he is under!!! You better start apprecaiting him and me because we are not going to be around forever.
"you BETTER start loving the people that LOVE you because we are getting tired of making things better for you without getting anything back,but a bunch of crap and crappy comments!!"

Sorry for my rant...but I felt like these skids need to hear the fact that as STEPPARENTS...we do it because we want to NOT because we have to.

The skids since then are really appreciative and have been "normal" in comparison to their usual "crazy". They are very aware now as to what their father is doing "for them" and for his family.

My fiancee is very supportive, partly because that is who he is and partly because we talk all the time about the skids and how to improve the situation for everyone - meaning, me, him and skids.

It's a different transition from having a 20something to little ones...especially when they aren't yours. Communication is key, you need to voice your concerns to your DH in a conversation or a note without losing your cool or getting angry. Easier said than done, but he needs to listen --- otherwise it's just going to be hell.

Also, you need to set-up a "date night" with your honey without any kids...this will allow you some quality one on one time with him...it sounds simple but it really really does work.

Though I know I ranted a bit, I hope some of my advise is something you can use or relate to.

Being a stepparent is a thankless job...but I hope to impact these beautiful children who are our future.