caught him on a dating site

I caught my bf on several dating sites, having conversations with several girls, that looked nothing like me. He said he never met anyone in person. I confronted him, and he finally accepted and said he regretted doing that. The thing here is I don't believe him anymore, and I have the feeling like he's still doing it or maybe something worse. He lives out of town and comes on the weekends when he's free but I feel like he might have another girl elsewhere. I feel so bad because the girls he looked for were the complete opposite to me (looks) and it's making me feel self conscious.