You may not like my thoughts, Mark, but you DID ask. (((( Mark )))))
I don't think her knowing you are "still invested" in the M is a good thing. I think it just gives her more rope to do exactly what she wants with the new framework she calls her "family"- meaning her new man and your kids, knowing if it doesn't work out, she can bring you back on board and insert you into your old position as her H. I think that makes you look weak and desperate. That shouldn't come as news to you, since you've been getting hit with those words from everyone on here. That's just from my female point of view. Take it or toss it.
That said, if you ARE interested in appearing more attractive to her from this day forward, I'd not mention any "let's spend it as a family" any more. You guys are NOT a family unit right now, with her new man living in your house.
Holidays are SO hard on families that are split up. HOWEVER, my philosophy has always been, (and one I believe I have convinced and exampled for my children) is that a holi-DAY is just that, a DAY, and can be celebrated the day before, the day after, the week before.... it's not about a date on the calendar. It's what you decide to make it whenever you get the opportunity. It's about people, and love. You can make it happy and special, regardless of the actual date. You kids will take their cue from you.
M-60 H-51 M-14 years BD 12/26/16 S 1/1/17
"First the pain, then the rising." Glennon Doyle Melton