Yeah, he was an asshole. Long story short, we were together for 9 nine months (my longest relationship at the time). Then we finally had sex (my first time), and within a month or two later, I found out that he was cheating on me, and he dumped me. I bawled my eyes out for quite some time after he told me, but when I was done, I felt a lot better, knowing that I was better off without him!
So if you ever catch wind that your SO is cheating, kick him to the curb, and don't waste any time doing it! You deserve better than that!