Well, it is tough being a step mom. But the reality is, you married a man with children. The children are not at fault for having a parent that doesnt want responsibility. I think the best thing to do is surrender to the fact that you may end up with the kids all the time. Life as you knew it is over. If the kids need to be at fathers house for more stability, then that may be something you have to accept. In my experience as a step mom, I had to accept the same fact. Fairness plays no part. You cant reason with an a*@hole. Your husband is the father and thus has a responsibility to the children no matter what the bio mom wants. To me it was easier to just take them and raise them then to fight with her and bounce the kids from place to place. Although it seems to be a thankless job, (read my blog) and the bio mom eventually killed herself, I guess God put me here in this situation for a reason. Someone always has to be the bigger person and swallow alot of pride and unfortunately it is usually the step mom. Even though things didnt go the way I had expected, I grew to love the kids just as much as I love my own. Who were not born until 2 years after me and husband were married, so I raised childrent that werent mine when I didnt have my own. What I mean by that is, I was young single and free and suddenly I became a mom to children that were basically unwanted by their mom. There was no more privacy and alone time. So, I sucked it up and did it. Take pride in the fact that you are a family now, no matter how screwed up it may seem. Good luck to you, I hope it works out for the best.

I think if you go to court and the mom doesn't want the kids very often, the judge is going to give custody to the dad with visitation to the mom, but will also order her to pay child support. Tell her it won't look to a judge if she is refusing time with her kids and you guys can easily be granted custody of all 3 & she will be the one paying child support! Maybe it will wake her up. A judge isn't going to take kindly to a mom who doesn't want to see her kids. Down side for you is you may end up with custody of all 3. But maybe she won't want that & will smarten up and take the schedule you're offering!

that if you do go to court about it, the judge will throw you both out. So what you are really fighting about is who gets more time WITHOUT the skids? Am I reading this right? Maybe I misinterpreted it? If not, then I would just give into her and continue seeing the skids as much as possible, and thank your lucky stars you even have visitation. She could be the opposite and deny visitation all together like so many of them do. When you have a kid of your own, it will be around all the time right? So what's the difference? I know they are skids and all, but they are DH's. This could actually work to your advantage. I mean if she creates a pattern of not wanting them around, you would have a good leg to stand on for custody in the future. Also, life can't stop just b/c skids are visiting. Dh must continue with everyday life, not put everything on hold. I understand wanting to spend time with them, but if they are there all the time, then surely he would not expect them to be glued to his side 24/7?

I could have written your post. We have the same issues with the BM. Ours also, when she does have them, drops her kids off at our bus stop on the way to work so they can ride the bus to school instead of dropping them off herself (wtf?). The kicker is that there's a stop right in front of her house, but this is another way that BM shirks her responsibilities. We wind up with the skids most of the time...in fact, they seem like my own damn kids cuz they're around so much.
I actually like having the skids at home with us because they are sooo much company for me while H is working night. And we have tons of fun and bond. Having them to myself while H is working has really grown our relationship way, way better than it was before. And because I'm closer to them now, I can say I love them...I'm beginning to feel more like they're my own instead of nephews or whatever...if that makes sense. I feel more bonded to them now, so I care about them and feel bad when they're hurting.
I'm sorry that my skids BM chooses to run amok instead of being with her kids. I have very little respect for a woman who could dump her kids as frequently as she does and see as little of them as she does. I can't imagine how shattering it is to them to have a mother so disconnected from their lives. I certainly don't paint myself as their mother in any way, I just feel like I don't harbor any resentment about having them around more than what would be considered "fair" because their mother doesn't want them. I can't help but feel bad.
Sorry for such a long post, but I'm trying to say that maybe if you change your feelings about the skids it won't be so draining. If you could maybe see that they're suffering and need you, or maybe find the fun in them, it might make it easier.
I hear what your saying though, and I am wishing you the best.