<human>: Condense the text into a few key points

I'm 23 male, she is 21. She moved here for college to be with me and that is when we started dating. She just graduated this Spring. We broke up fall '10 for 6 months because the romance was dead, got back together in the summer, dated another 6 months and broke up in January because the romance wasn't back. I'm still in love with her, but the feelings aren't mutual.
The issue now is that I still see her around a lot because we are in the same social groups, have mutual friends, and work on a business venture together (there is a group of people involved). She asks me to do functional things together (which last time lead to us getting back together) like help her move, directions somewhere, or stuff for the business. I try to avoid her, ignore her calls/texts, but I just miss her and end up giving in because I care about her and want to help her with whatever she needs. When we are together she is flirty and we end up having weird moments with prolonged eye contact, but if I attempt to elevate anything she shuts down. I have a friend who says someone she dated a person for 5 years who is a great guy because she knows he still has her back with stuff while lots of guys can be immature and bitter. I guess I'm modeling my behavior after wanting to feel like that, but at the same time I might just be being used. What sort of advice would you give for dealing with a situation like this or ex's in general?
<bot>: I'm having trouble getting over my ex because she keeps asking for my help with stuff and I have to work with her too much.