I don't know what to suggest. I am in a place right now where I feel so good about myself that I'm afraid I'm going to tell everyone to make my choices. That's not fair to do and so I'm trying to just observe.
I observe in your case that you spend a LOT of time with your H and that it never makes you feel better about him or about your M.
Also that it doesn't necessarily make you feel better about his relationship with your D.
Also that I think it maybe impacts your relationship with your D because... guessing slightly... you sometimes want to make up for his inadequacies with her?
That last one is maybe mind-reading because it's something I am trying to keep from doing myself. So take that one with a grain of salt.
For myself, I felt better... cleaner... when I didn't go through the "happy family" rigamarole. But I have very little time away from my kids so it's easier for me to say no to STBX because I'm not sacrificing very much of my kids. So again, grain of salt.
I also observe, at my house, that my kids have SPECIFICALLY said that I'm interesting and fun NOW. Given the way STBX and I tiptoe around each other when we're together, I think the contrast is clear to them and therefore I don't want to spend time with him, where I am shrunk and clearly unhappy, and have that show to my kids. So FOR ME, not spending time with him as a "family" is healthier for my kids than putting on that particular show.
That said, S7 still calls us a family of five, and I'm not sure how the D announcement is going to land on the kids, so it's not like this is all rainbows and butterflies, either.
I think it's WONDERFUL you spent a whole evening watching Downton Abbey and reading half a novel. That's WAY better than being paralyzed by your sitch. And you probably felt refreshed in the morning, too. Why beat yourself up for that?
Me42, H40 D12, S8, S7 A revealed: 7/13 Sep 4/14; Agreed to D 1/15