What do you when you find things online about your boyfriend..?

Well here it is my cousins and I were online and we each typed in our boyfriends' screen names and found some interesting things like personals from different sites and things like myspace, red light social center. With my boyfriend I found him all over the place even in red light social center and on it a girl is claiming he's a good 'uck and he's claiming she's his future wife when with me he keeps telling me he doesn't believe in marriage. I found him at other personals as well dating back to 2005. We've been together for 5 yrs this June. I already emailed him a list of the sites and I've noticed other things as well in his myspace he's single, on his AOL page he's single, everywhere he's single except at this red light place he's in a relationship now I have to wonder is he in a relationship with this girl or with me. Now I'm just trying to figure out how to react to all this. I thought I loved him, I feel like I do but I'm not even sure anymore of my feelings for him. Or his.