Whether it's romance, friendship, family, co-workers, or basic human interaction: we're here to help! So my friends will probably make fun of me the rest of our lives.
This may be a distinction from your situation; I can't speak for your boyfriend if he's openly flirting with others.
Regardless, you can do further snooping if you want to.
Is there something keeping you at a distance from him? You don't get a free pass.