The long and the short:  Divorced guy who's ex had several long term affairs and have now been single a number of years.  I have been in one serious relationship post divorce.

It took me a long time to get over my ex, while I was not blameless in the deterioration of the marriage, she was both unfaithful and untruthful.  I was emotionally scarred for years, unable to trust anyone and picked up a crippling anxiety from dealing with her or seeing through her lies.

Fastforward to two weeks ago.  At this point I was doing well, physically and emotionally.  Though I had bouts of loneliness, I had established some new friends and I felt like I was in a good place.

For the sake of length and graphic detail I will summarize, but essentially  I had marathon sex with my ex.  Like a fly trapped in a web I accepted the initially innocent invitation, which led to it.  Alcohol was of course involved. 

Afterwards she wouldn't speak to me, then told me it would never happen again, which I was fine with, but I at least wanted to speak about it like adults.  I felt manipulated like I was a test subject, just to see if she could still pull it off, then cast aside.

I now find myself back where I started, riddled with anxiety and I cannot stop thinking about her.  I know it's my fault and I know I was weak, that doesn't make me feel any better.  I will also add that the experience was definitely not healthy for either involved.  

Has anyone else experienced this before?  Going back to an unfaithful partner only to be cast away a second time.  I am not sure what to do and am having trouble concentrating or enjoying anything and I feel like a complete jackass.

Thanks for listening.