Personally - I don't think the Boyfriend should have any responsibility here until they are married. DH has it in the Custody order that the spouses have first obligation. Our BM had no option but to have us help unless she married her BF. So she did last month. Now it is an even playing field. Our BM has the same crazy schedule and it kept interferring with our lives, now we forced one week on and one week off and it is much better for all of us and especially the kids.

We have the exact same custody schedule!!!!
As for what you say--- I wonder with a little bit of deep breathing, and if your DH sets up the situation well, if this could be an opportunity to have a conversation about the needs of each household and to tweak the schedule accordingly. I am so hoping that this can happen in my life at some point soon--- b/c all of the back/forth ("negotiations" as my FH calls it) is really not about the kids. It's about the adults, egos, etc. And perhaps (as in my situation), dysfunctional patterns and ways of relation between DH and BM that have been established and ingrained for a long time.
I am hoping that at some point soon my FH, BM, her husband, and me can do this. B/c each household/family needs to have a schedule that works for them (the child being a part of each household), each household needs to be treated with respect, and it really needs to be about those things-- not the egos of the adults involved (which it is, largely, in my case).

At least she has a job right? Maybe she's going all wonky because she scared of losing her job if she can't make arrangments for kiddo.

"The beauty of life is, while we cannot undo what is done, we can see it, understand it, learn from it and change, So that every new moment is spent not in regret, guilt, fear or anger, but in wisdom, understanding, and love." -Jennifer Edwards

Well, in the end, it would only be hurting ss right?

Wow, sounds like a crazy BM alright. Everything on their terms...it's their world and we are just living in it apparently.

My suggestion is treat her like the child that she is, mentally, put her (BM not the kid lol) on a structure and do not deviate from that, it becomes much simpler. Once the BM in my situation realized she had no wiggle room, the excuses vanished. DH told her if she can't handle her court ordered days, he would gladly take them off her hands, but she would be getting none of his days. Of course she threw a fit, but what is she going to do besides spend the time and money to go back to court? And what's she going to do in the mean time?

We play hard ball. It's the only way she understands her boundaries, we do not deviate, we do not compromise, and we do not play games. Her power to control and manipulate is so far reduced from what it was, that we can finally function without worrying the way we used to what the next drama is going to be.

I had shared custody for 15 years with my ex for my DD. On my weeks, I figured out child care. On his weeks, he figured it out. Simple. SMN, pick him up if YOU want to, if it works for you, but don't feel obligated, like you are on call. That is just more BM game playing, power trips.