New to the 180. Help?

[G_Main]

I had a major set back last night, all the way back to square one.

Found out my husband has been sleeping with one of his prior students. Theyre both Marines and she's 19. Hes significantly higher ranking than she is. He "cut it off" because he didnt want to get her in trouble.

He also said that a mutal friend of ours confided in him that I was delusional and still fighting for our marriage and thinking he would come back. He was nice enough about it, but just said "stop fighting. I'm not coming back. move on."

I feel stupid for taking little things as signs that we were improving. Things like he hasnt filed the papers yet and that he was being nicer to me. He said he was just being nice to keep me happy so I wouldn't crucify him for the affair. He said that he was worried that when this didn't go my way and that he didnt come home that I would be vindictive.

I've told him again and again that I have no interest in ruining him.

I'm completely back at square one. I need some encouragement and advice.