My husband and I split up in September, yet since January we have been having sex a lot. He led me to believe we had a chance of getting back together right up until last week when I found out he was shagging some other bint behind my back. Now I have to take myself off for STI screening as he has been shagging her using no protection then coming back to me. He has blatantly used me and led me on and now I feel vengeful. Although it is very childish I have the overwhelming urge to tell them girl he has been having sex with me whilst he's been seeing her. What would you do????