online chatting

I have been with my boyfriend for almost ten years. We have lived together for at least eight. I will admit it was a bumpy road, but we have always managed to pull it back together.

My latest vent is over the past three or four years I catch him on internet websites chatting and getting to know girls. At first it was really bad! plentyoffish dotcom and other major adult sites. He peomised to quit and swore it was only me he loved, and he has never met up with a chic nor called any...Things would go good for a while, But then I would find a different sight. Same thing. Now, almost four years later, I caught him deleting cookies and history.... I'm like wtf!!! How could he say he loves me and wants no one else.. when he is hidding this from me?? He doesnt see how it is different from me talking to guy friends I grew up with, or even friends of the family online. I didnt meet these guys at a dating site or chat room, PLUS he knows about these people! I have no secrets from him! I need help understanding why this is such an issue in our relationship. Is it worth leaving him over? Or am I just to jelous??

Any help and or advise would calm my nerves!!

Thanks!