Poly, I'm glad you can relate to this...it is something I am wrestling with.
IN, I think my situation is unclear. My husband and I live as domestic partners. We don't sleep together, and rarely have sex. The "four nights" (0r three rather) that he is home 1 is family night. 2. Is getting ready for the work week. 3. He takes my son out so that I can rest for awhile.
She DOES get one night - she has for a year. To have this one night I have to take care of our son and house for another 24 hours.What might feel good is if I could go to a hotel once a week, spend the night and rest! People here have critized me for this. Actually, I'm a really loving person. I have struggled hard to make everyone happy. But there comes a time when I need to learn to put my needs FIRST.
I do think, or an finding that, there are complications when a single person dates a married person with kids. Part of this complication is that she wants only PART of my husband, the sexy fun part. I do think sustaining a long-term relationship (even in poly) takes accepting someone as a whole. That wouldn't mean her dating me, but say, her occasionally inviting him to do something for the day with our kid. Or coming to our neighborhood for dinner out with him, or meeting him for lunch. I'm not asking him never to spend the night, just that because of circumstances, a family has to come first.
If I were single, whether i dated a guy in a marriage with kids would depend on my needs. If I wanted to be part of their family, that would work, but if I needed to only have dinner a few nights a week, that would work too.
But I feel my husband's GF really wants a primary partner. I get this from the fact that she often avoids things to do with his family and friends. She wants him to be in her circle and on her time schedule. And, from a practical standpoint, thas not entirely possible.