I don't know...

Ok so I've been with this guy for 9 months and things were going good but the past few months he's been more interested in his friends Than talking to me. Well this other guy that I'd liked for a while and I started talking a little and I like him more than my boyfriend. I don't know how he would take it if I broke up with him because we've talked about having a future and stuff... what should I do?