Is he my friend or not

Hope anyone can give me a little bit of advice, two years ago my partner and i broke up after 9 years and although it was difficult to get over, all in all a good decision.
Last year i managed to fall for his best friend!! I saw him on Sat and we got on really well, should i pursue this? my ex is now with someone new and very happy with her after 1 1/2 yrs, maybe enough time has passed?? Not even sure he likes me, i think so but then he pulls away when we get too close?
Pls help x

Dangerous!

This is such dangerous territory. I think you need to be a bit more sure about what this guy thinks of you.

If you do hit off and decide to make a go of things, just be prepared for some fireworks. It could also mean the end of your ex's friendship with his mate.