What do I do? .?

Okay, so this summer I almost fell for this guy. But he had a girlfriend so I backed off & we became best friends. Now I’m in a relationship & I’m in love. But the guy now is out of his relationship & likes me. I’m not sure what to do because he is probably the better choice but I’m not sure what my heart wants. My boyfriend is quite a bit older so there is a strain on our relationship. But the guy fits perfectly into my life. My boyfriend said if I wanted I could date the guy & see how I end up feeling & that he would wait for me. But I don’t want to hurt him. I’m at a loss.