Is it right for me to be angry at? How do I end this emotional turmoil?

a coworker that I have been ual with. He never made any promises to me, but he knew I had a crush on him. Actually, he has a gf overseas and I knew it. But I didn't want to see that he was unavailable. I've been ignoring him since he flirts with another girl and I'm suspicious, they have something going to. Though, I'm not sure. He emailed me today, but I ignored him. Am I doing the right thing? My coworkers are looking at me like I'm being mean or I'm being childis