Welcome. Sorry that you find yourself here but I think if you stick around you will find an awful lot of support.
The hardest thing for you to do right now is to stop putting the focus on her. You want answers and you may never get them. You will have to get to a point where you will be ok with that. Try to get yourself to a good spot mentally because this is not a short ride. Try to do some things just for your own well being whether that is jogging, meeting for dinner with friends or the gym.
If you continue to put the focus on her, it will drag you down so quickly and you will start to do things like begging and pleading. I've been there. I became someone I didn't want to know and I was miserable. No wonder he didn't want to stay.
The big thing here to remember is that the only person that you really have any control over is you. Make yourself an attractive choice, make yourself the choice.
keep posting.
kat
Me-53(and learning!) S24, S21, D18, D17 Just keep swimming, Just keep swimming. Dory