I'm sorry you are having such a rough time, G. I think you did right in being honest with D12. She is getting older and naturally more aware and inquisitive so I don't think that you did anything wrong in telling her the truth. You didn't call her dad names or anything, just matter of factly explained the situation. Still I am sure it wasn't easy for you to say or her to hear, but I think it was probably a good thing. You are a great mom and your D knows it and she will forever be grateful and you all will always have a strong relationship. You may not see it until she is a parent herself, but I guarantee you she will parent by the example you have laid out for her.
As far as M, I'm sorry you felt kicked in the gut. Good for you swiping left! I think all of the stuff you mentioned (the tux pic, wanting kids) are just his way of trying to put his best foot forward. What you should remember, though, is that you saw the REAL M. The one who couldn't/wouldn't commit, who valued his own time and preferences over yours, who was more than just a casual, occasional toker. While that isn't coming out in his profile (and of course it isn't, because who would own up to sh!t like that in a dating profile????), some sucker is going to fall for that and then get the same version of M that you did. I understand the kick in the gut and I am so sorry you are feeling it, particularly on top of everything else.
Hang in there, G. If we weren't a hot spot right now, I would tell you to pack your bags and head south for a few days and just hang out. Try to relax and do something fun/nice for yourself. I'd send you some happy mail if I knew your address.
Me 52, H53 Bomb drop 9/29/2014 Divorce from XH final 12/17/2014 Marriage #2 12/31/2019 5 adult (step)daughters (3 from XH's first marriage, 2 from current H's previous relationships) 6 grandkids