Relationship advice please

[twinkle21]

I'm so confused its drivin me crazy.My boyfriend and I have a fantastic relationship and have been together now for 3 years.Only last week I found some pictures of a girl on his laptop (normal pics) whilst loading on some other pics as a surprise.I confronted him about it in a nice way and he explained it was a girl from work.I did wonder why she'd emailed him pics of herself and she was a very attractive girl.I forgot about that anyway and then a couple of days later I was using his laptop to do some work and went into his history of internet pages to find this website I needed and found that basically he'd registered himself on a dating site and he had looked at loads of girls profiles. To cut a long story short I asked why and he said he saw an email of mine that I had left on my computer by accident and it said a guy had seen my profile and thought I was hot so he assumed I'd put myself on a dating site and he was trying to find me. Only I've never seen this email that was supposed to be in my account. He then sort of accused me of deleting it incase he saw it and I just couldn't believe it. I then found I was the one trying to proove my innocence. That was 4 days ago and although we thought we had it cleared up he hasn't barely touched me since and I'm finding it hard to even get him to look at me. We live together so as you can imagine- its hard. I'm so upset I don't know what to do. I almost feel like I should just give up as I have done nothing wrong and I'm a good girlfriend only he just doesn't seem interested. Before he couldn't leave me alone. We talk and have a giggle at things and if I go for a hug he gives me one only he never comes to me first like before. Now he's suddenly gone out supposedly meeting friends but I'm just not sure if that's true. Something just isn't right and the change has been just instant. I'm sorry if I've gone on and on, I'm just a bit all over the place at the moment. All advice will be greatly appreciated x