My husband (67M) and I (50F) have been together 2.5 years and married about 1.5 years. He has twin daughters (almost 16Y) from his previous marriage to "Heather".

Heather has been remarried to "Bob" for about 8 years, and while my husband and his ex share custody, the twins live with their mother and visits my husband every other weekend. They also have family dinner together every Wednesday night so that my husband stays regularly involved with what is going on in their lives, how school is going, etc. They have had this arrangement before I even knew him, and it actually works out well as I can go have dinner with my adult kids and have time with them.

However, Heather has a persistent habit of making vacation plans and activities over my husband's visitation weekends. Just this summer, they were gone nearly the entire summer, visiting Las Vegas, Montana, Minnesota, Paris, and their beach house. I believe that all summer he saw them one weekend (not an exaggeration). My husband doesn't protest even though he doesn't like it, mainly because Heather is a live wire, and he is concerned that she will try to exert even more control or cause a scene. Also, he wants his girls to have every experience that they can, so he would not deny them the chance to travel. Heather already acts like her current husband is the girl's father, so there is that element as well. It might be different if Heather ever asked if it was alright or consulted, but she just dictates.

As for me, I try to stay out of all of it. Heather and I had one big argument about 1.5 years ago, and even though she was being ridiculous, I decided it was not worth my time to argue, and I don't want to be the "excuse" that causes Heather to try to withhold the girls even further. She and I are both strong women, and I am normally the direct type, so I feel I have to tamp down my own emotions in sake of peace, and because I love my husband and value his relationship with his girls, I have been willing to do that.

Fast forward to current aggravation. After not seeing the kids all summer, school is back in session and the regular schedule is back in swing. The girls stepfather, Bob, found out in the spring that he has mesothelioma, an incurable cancer, and is undergoing cutting edge therapies and treatments that have only saved a few patients to date. Treatments are going OK overall, and he has not been given any prognosis like you have so many months to live. Both of us like Bob very much and are being supportive in any way we can and hope for the best outcome for him. Because of his treatments, he just started spending the workweek in a city about 2.5 hours away and is coming home for the weekends.

This weekend is my husband's weekend. The girls stayed the night Friday, and this morning he woke up to a text from Heather saying that the girls contacted her and stated that they wanted to go back home by Saturday dinner so they could see Bob and spend Sunday with him. I could tell my husband was hurt, but he agreed because of the cancer situation. I asked him if he was alright, and he said he was annoyed, but that he doesn't know how much time Bob has left so he didn't protest.

I am upset for him. I understand the situation at hand, but he is also their father and deserves to spend time with his kids. Heather is not the type to say girls you should really spend time with your dad - she will do whatever the kids want, or maybe what she indirectly encourages them to do.

I don't want to get in the middle, but I also don't like to see him hurt.

I am looking for advice from more experienced step parents.

EDIT: I will be more blunt to clarify. The BM is a control freak with a trigger temperature. Everyone tiptoes around her because she is known for being unreasonable in her anger.

For example, the fight I referred to having with her was over the kids room at our house. They have an upstairs loft type area with an attached bedroom and bathroom. The loft area was not being used...it just had a couch and really nothing else. All thr kids are into arts and crafts, so I proposed to my husband to turn the loft area into a crafts room. He said yes. In order to do this, we would have to block off a window in the area, which meant that we would need to move the fire escape ladder to their bedroom.

Husband brought this up with the girls at family dinner, which was a mistake, as this then involved the BM in the conversation. The girls didn't want the ladder in their bedroom (for context it is a small portable ladder you can put in a window to escape and it can easily be tucked out of the way, and we explained it was because of the craft room set up. The BM's face turned cold and hard, and she looked my husband dead in the face and said " if you make them so this, they will not want to come to your house anymore and I would support them". Stunned, I asked her, "Don't you think you are blowing this out of proportion?", and she didn't even look at me and stayed staring at my husband and said,"No, I am not". I was so pissed that she was being ridiculous and threatening my husband that I removed myself from the table as I was obviously angry and about to explode. The children and her husband told her she was being unreasonable, and the kids told her what she said was not right, but she stood her ground. Things were very awkward, so after several minutes I asked husband if we could just leave to difuse the situation.

After a day or two, I thought I would try to smooth things over so I texted her to attempt to open the door for a mutual apology, and she still did not apologize for what she said. My husband said that she never apologizes even when she is clearly wrong.