Most Helpful Girl
There are a couple of reasons she did this:
When I did this it was because I wasn't really over my ex. I know you don't mention a lot about that, but it could be a reason. Sometimes the nice guys do finish last. The thing was, you showed her that there are guys who cared and who acted decent and loving and this probably helped her even if it has been months since they broke up she could still have feelings for the guy.
There's also that whole "spark" thing. Girls insist on a "spark" needing to be there and sometimes with a guy that is perfect (funny, smart, cute, caring ect...) if the so called spark is missing then we spend more time thinking about the lack of a spark than we do about the actual guy and then it just gets worse.
You guys didn't fight so I won't even mention that.
If you want her back the easiest way is to be unavailable- fake indifference (its worth it!). Its easiest if she agreed to stay friends in which case you can ask her after a week or two if she would like to go to the movies or coffee"as friends". Act like a friend on these occasions, don't linger on the hug or try to hold her hand. Do not tell her you miss her or talk about the break up. In fact talk about anything except the relationship and act completely casual as if this was a normal meal with a friend you had no feelings for. Back off for a couple of days and do it again. This time though tell her she looks pretty offhandedly and continue as if nothing happened- don't give time for it to get awkward just launch into another story. If she texts you respond, but always be the one to say goodbye first. The trick here is to remain unavailable.