Getting Attached

This isn't something that happens every time, but it does happen - without warning. When I'm seeing a guy and "feelings" get involved, so some unknown reason I get attached. And I mean A-T-T-A-C-H-E-D! Once I feel this way, I put up with a lot of crap (and unfortunately recieve a ton of it). Why you ask? I. Don't. Know. I don't know how it happens! I wish I knew... But once I'm there, there's no turning back and it's a slow very painful process to get myself back out. Unfortunately for me, I have the terrible habit for gettin attached to the "I don't want to date" guy. Boo...I hate that excuse. You mean - you don't want to date ME. And that sucks. But only once I've emtionally velcroed myself to someone. Any other guy, I don't even get around to asking if he wants to date cause, I don't giva!
I'm currently trying to detach myself from a guy I've been going back and forth with since December. It sucks. I'm crushed. But it has become painfully obvious that he only speaks to me for one reason - and it's not cause he wants to date me. I don't know how I got to this point because if I'm honest with myself, I'm not ready to be in a relationship with anyone, but I want to try with him. He's fun, cute, and he's...well...he's a big teddy bear and I like that. Oh well. I'm getting over it every day. I just don't know how he got under my skin like this so quickly...

Suggestions on how to avoid this emotinal stickiness in future would be most helpful...