Nope.

Where is BM?

Categorically no.  You have absolutely no duty to take care of your step child.  Visitation is for the benefit of the relationship between the child and their biological parent.  If your husband is away, his child should not come. 

No. My DH would love this to happen when he's away (not now due to Covid) but no. I put my foot down and oh boy there were arguments! I did not back down in spite of allllll the guilt trips tried, but she's a good kid, she likes you, my therapist is surprised you won't, she's not difficult, etc. Yeah DH but you're asking me to be the responsible one still, I'll still have to take care of her etc. Not my kid.

The only thing I agreed to was two nights, and one of those plus a day she'd be at a friend's house.

He's never tried it again.

Besides if I'm told clearly I'm not a parent, don't expect me to suddenly start parenting because it's convenient for you.

No!

In the event you need one more - this is not your responsibility.

Your husband is manipulating you and using you.

If your DH was concerned about "spending time with family, " he shouldn't have taken a job that has him away from his for 6 weeks at a time.  How often do these weeks-long out of town trips occur? If it was once a year, so that maybe you were dealing with 3 solo weekends with SD, I might consider it to keep the peace, even though you have absolutely no responsibility to take her in his absence and should NOT feel guilty if you don't. Any more than that and I find his request that you take her against your wishes to be unreasonable.

One thing I'll add - I have DD1.5 and SDs 6 and 8. My DD adores her sisters and loves when they're in our home. If my DH was away, I would consider having the SDs come anyway to "spend time with family," but it would be for DD, not for DH or the SDs.

He is manipulating, and using you, to an extent.

Him making you feel bad, saying that "she need to be with family", is manipulation; he is counting on your guilt.

He is using you to care for his child, when he is not even there, so he doesn't have to come up with an alternate solution. Does he really think it's in his daughter's best interest or does he just not want to tell BM that he can't take her on the weekends he works? Personally, I think it's in a child's best interest to be with a parent (unless parent is unfit), than a step parent. Especially when they have not been taught to respect the adults in their lives.

Ugh, no! Perhaps you can agree to have her over for an afternoon every couple of weeks, or whatever works for you, so she can see the other kids in your home, but no, it's not your job to take her when he's gone.  And honestly, he's a jerk for insisting on it.

He's using guilt trips to coerce you into being his free babysitter. 

She's not your child. You're not her momma. You're not responsible for having to parent her. She has two parents - her bio father and her bio mother. Your relationship with her should never have to require giving her consequences.

Just say no. If he's not there, she's not there. She's not going to feel rejected unless an adult tells her she should feel rejected. I hope her parents are grown up enough not to do that. 

I was in your shoes when my DH decided to exercise his right to two weeks uninterrupted during the summer, but opted to work through them. I was working too, but I was working from home (since long before it became a thing) and he thought his little angels wouldn't be any problem for me. Um, WRONG. 

I put my foot down and said never again, and in addition if he left the house during visitation even to run to Home Depot to buy a nail, they were to go with. 

Because I am Not The Momma. 

Negatory.

Not if you don't want to. In our situation, I have kept ss but I like him haha. If you don't want to, send yours back to bm. Dh can get over it or get a new job 

Many CO's will even have a ROFR which would mean that if he can't be there during visitation, his EX can claim that time as hers with the child.

While I am guessing part of the "visiting family" also relates to her half siblings... the primary factor here is that HE is not able to be there as her parent and he is missing that time with his child.

What should happen is that due to his new schedule, he should work out a different custody arrangement with his EX.  Maybe that  means the child is there "every weekend" (I'm assuming he gets EOWE?).  that he is not working the 6 weeks.. and none of the weekends that are his scheduled work weeks get assigned to him as custody weekends.

I don't think it would be as big of a deal if it were just the occasional day or so during his visitation that work or some other obligation pulled him away.. but it shouldn't be a regular and long term situation.

When his job schedule changed so drastically.. He needed to look into adjusting custody time so that he didn't lose all that time with his child.

I might turn the guilt back on him and ask why he doesn't want to have time with his child.. because by refusing to change the schedule so that more time falls on his "home" time.. that is what he is doing.. shirking his parental responsibility.. off onto you.