I have never thought of pouring out my feelings on one of these sites before but Iive reacherd the point where I don't know what to do. I would appreciate any advice people have to give.
I have never been a jealous person and then 2 years into my now 5 year relationship, my partner (a lecturer) was inviting a 18 year old round for tuition (I had joked about her having a crush on him, he laughed it off) and I found a letter revealing her whole obsession.
He put an end to it after a long discussion and then a year later started a very close relationship with a girl he had met on a course.
In company she would hug him, stroke his hair and hold his hands and I stupidly said nothing. He denied there ever being anything wrong and two years later his friend (who had gone out with her)informed me he no longer speaks to my boyfriend because he had slept with his girlfriend on and off for 2 years.
I once found a book she had give him. About a relationship destroyed by another woman and inside she had written...'I hope you find this as accurate as I did'. When I found it he denied ever knowing the message was inside the book or any relevance the comment may have.
Since then I've been challenged to wonder, why is his condom pile decreasing (we don't use condoms)? Why has he put himself as single on two social comminication sites? Why do I never see his female friends and why every time I bring up the subject, he reacts very badly and leaves me feeling I am completely paranoid.
I do not have a history of jealousy. No man has ever made me feel like this. There comes a point where your strong instincts are challenged so much you feel perhaps I am going mad, perhaps it is me? And, will I ever be able to trust this man again when he doed not do anything to gain my trust?
Please help.

dear, and i may be wrong, but from what you say it really seems to me that he's cheating on you...

the only thing i know for sure, it's that if he loves you, he should show his love and do anything to gain your trust once again... if he doesn't, i don't see why you should suffer for someone who doesn't care when you are sad etc