Well, I think from what you are saying, you are carrying the trauma of your past relationships into this one. Sometimes women have a six sense about things but unless you are seeing more than you are writing about, I think you should back off from this and not over analyze it.
I have snooped on my husband quite abit but he deserved it. He had a secret Myspace with exes on it that he communicated with. Took a long time to get over that. I think the reason we do this, is the more we care about someone, the more we fear the hurt that could result if history repeats itself. But, we can't control other people, and love is risky.
You may need to see a therapist for awhile to work through the trauma of being cheated on so it doesn't contaminate new relationships. You are starting to care for this man, so your anxiety is rising and getting the better of you.