Feeling Cheated - From Anon Partner

Hi.. I have been reading through your brilliant site and came across some stories about prison pen pals. I already knew my partner before he was sent to prison and we had been together on the out for 4 years. Whilst he was in prison he started writing to a woman. I found out because he was up front on a visit and told me. He said she was just a friend and although I was angry about it I accepted it because I thought that just getting letters off me would be a bit repetitive so I just accepted it. He has been out of prison now for 6 months and I have just found out that he has been meeting up with his lady pen pal in secret. I stood by my man for 5 years whilst he was in prison and I feel absolutely cheated and gutted. I am not sure where we go from here! Yours Anon Partner..