need an honest opinion!

My best guy friend's old college roommate and I have been hooking up for a few months. The first time we did it, my friend got upset at both of us. His reasons included not wanting to feel like a third wheel (the two of us are his closest friends) and feeling jealous that his friend was getting some and he's in a prolonged dry spell. So many of my friends think it's because my guy friend is actually in love with me, but I didn't (don't?) want to believe that. I thought I could see myself really liking this guy and wanted to give it a shot with him. We got along great, had a lot in common, and we were really attracted to each other. We decided to keep our trysts a secret in the interest of not upsetting our friend or dealing with the situation. I'm not proud of this, I know it was the cowardly way out.

The roommate just called things off with me because he said he couldn't continue sneaking around behind his best's friend back. I agreed that being shady wasn't really for me either, and I'm actually a little relieved that it's over. But I'm wondering if that was just an excuse because he's done with me, or if he's truly realized that what we were doing was kind of awful? If a guy really likes you, would not wanting to be a bad friend really get in his way? Wouldn't he maybe try to talk things out with our mutual friend if he really wanted this, or do you think that he's also wondering if our friend likes me and knows that no matter what, a relationship between us would never be okay? Brutal honesty welcome, though I already know I was being a sketchy bitch so no need to call me out on that :)