How do you get over a crush that you only like the idea of being with?

Ok how do you get over a crush on someone? My mom has this group of friends that come over to play music at her house a couple of times. I'm friends with them too. There is this new guy that's like 50 something. Despite his age I've kind of developed a little bit of a crush on him. And I want to keep going to music at my mom's but I don't think that's going to help me to not have a crush on him anymore. It just sucks because I'm trying stupid online dating right now and then it's definitely not going awesome but it's not going terrible. I just don't know if I have the patience for it.