When u look on craigslist for something, aren't u in the market to buy it? Jesus woman! Look at the signs! Yes he is gay or bi. And yes he is a cheat. I hope u broke up with him for doing so. Don't wait until he gives u an incurable std.
Could mean he's gay, could mean he's bi but if it's all behind your back then his sexual orientation is definitely "Lord Fuckface Dickhead, the billionth." I mean at some point "just looking" will turn to "just the tip" And you know the rest.