Well, I know all three feelings (I love long hair but part of me would love to cut it, but I love long hair more so I don't).
It's your hair, so it's up to you, but I agree with the first commentator, unless you know him really well and for a very long time, he's probably going to loose interest after cutting your hair. So don't .
All of my girlfriends have had long hair, and I haven't cut any of them any more than a trim. I've not even told any of them I'd love to cut it, just to avoid the chance she might agree and I'd be caught in a serious dilemma. Because at that point, I would not know how strong I'd be.