Would you refresh my mind about something, please? You said you were giving it a year before you filed for a D. Is she aware?
I see a lot of behavior in her that is common in WW's who are applying pressure on the H to file for the D, leave the home, or whatever. She will find the negative side to almost everything. She will make inconsiderate statements, just as she made about dating college men. The standards that may have once guided her life......and the role model she tried to be for her children, have been cast aside. She may have thought the 14 year old D would see her as being a cool mom who could get young college guys! Maybe she expected everyone to be as excited for her.....who knows. There are times WW's are just inappropriate.......period.
Resentments, unmet expectations, selfishness, self entitlement, disrespect.........whatever led her into developing a wayward mindset took a little time. It didn't happen overnight (even if it appeared to you that it did). What you are currently seeing is her rebellion. Anyway, she doesn't realize her family is still in shock from her news of wanting to end the M. She acts as if they should be just a well with it as she. That's why her attitude of, "What's the big deal". So, whenever the H expresses any objections to some careless or inappropriate statement or action on her part........she is ready for a fight.
It's one thing to call her hand on being inappropriate or disrespectful, but don't make passive-aggressive statements that's going to lead to an argument. Don't have a discussion about it, b/c it does no good. She will turn it into a argument/fight. If she tries to bring up later, shut it down and say, "No more talk about it".
This is just one of the reasons I don't encourage family traditions or special events within the immediate family when the WW is talking about leaving. The WW will usually (not every time) spoil it before it's over. You were put in a situation where she invited everyone to celebrate Mother's Day, so you felt stuck. One advantage you have with your kids being as old as they are, you can let them plan Mom's birthday or whatever. (Let's see how much she makes over you on Father's Day). Also, the following months might be a good time to change some things around, instead of sticking to traditions. If the kids enjoy it.....and if a divorce should come, then it may help that first year following it. Family traditions are wonderful, until suddenly one, two, or more people are missing from the family........then their absence seems magnified. In less than five years, my family lost so many members, either through divorce or death, that we struggle a lot. When I try to have those traditional family dinners, it can be emotional painful for those of us left. Anyway, do as many activities with just you and the kids, as possible.
((hugs))
It is not about what you feel should work in your M. It is about doing the work that gets the right results. Do what works!