I found out H was dating when I caught him at his place with someone else... We had been separated a couple of months and he swore that he wasn't dating. (I knew he was on a dating site a couple of months before this, but never confronted him on that).
He said he was then just casually dating. I later found out he was sleeping with OW, someone with whom he had started an EA before leaving. At first I didn't confront, but he became sloppy about hiding it, and I finally confronted him - in a very ANGRY way. I tried to guilt him, judged them both and it all backfired. I just pushed him more to be with her because I was so angry and I just wanted to be right... Bad idea.
My second mistake - when I first found out about his lies and dating, I confided in my two SILs. I am very close to them and they have been part of my support group. I was desperate and grief-stricken. I begged them not to judge him or tell anyone.
Long story short, someone said something and when H recently tried to introduce OW to his family as a new girlfriend and legitimize his R with her, he found out that his sisters already knew and he was furious at me. He accused me of trying to badmouth OW and ruin his R with her because of my jealousy.
Very, very bad ideas and I live with the consequences of my mistakes - and my H's anger every day.
I just hope this can help someone else not commit them too..
Me & H: 44 D7, D6, S3 Together: 20y, M: 17y EA: 11/13/10, Sep: 12/23/10 EA becomes PA: Spring 2011 H filed for D: 09/06/12 D Negotiating began 2/15 OW seemingly gone on 3/15 Still negotiating D