Private message from a friend on Facebook asking me to tell my fiance to stop texting her.

Hi, I've been with my fiance for 9 years and we are getting married in 6 months. We haven't been getting on recently, or had sex in over a month which I had put down to wedding stress, doing lots of overtime in work etc.

I received a private mail from a friend (not a close friend, an ex colleague from my last place of work) asking me to telly fiance to stop texting her and sending her private mail on Facebook. When I asked her what he had been saying, she replied "just stuff" and she didn't know how he got her number.

I asked him about it, he denied sending her texts and Facebook messages. He said he didn't have her mobile number. I asked him for his mobile which he gave to me, and her number was in his contacts, but there were no messages either to or from her. Ditto for his Facebook account.

Is he cheating / sexting or am I being completely paranoid? Aaargh, thanking you for your help!!!