Guys, Why do men approachy you if they aren't single?

I was approached by a man at a party who showed interest in seeing me again. I messaged him as I was already following him on Instagram, he asked when he could see me because he wanted to find out more about me. We arranged to meet, however that didn't happen due to travel issues. He didn't show any further interest with regards to communication. We eventually crossed paths again and the communication was off. I found out he is in a relationship. Is this the reason for the strange behaviour?

Guys, Why do men approachy you if they aren't single?
Post Opinion