Just wanted to say I have an alcoholic parent--along with numerous alcoholics in the family tree--and I waited until my 20s to even try alcohol out the same gigantic fear I'd instantly become a drunk myself. Thankfully it didn't catch on for me at first. But I got to a point this year where I was so irritable and mad I wanted a drink because I knew it would calm me (alcohol doesn't make me wild or crazy, just makes me kind of tired and gives me a headache)---I immediately went to my P-doc cause I knew that was a bad sign. Worked on my meds, and to this day he sees nothing wrong with me having a drink every once in awhile, but I'm afraid to risk it.
As for the man/boy troubles, I haven't been in your exact situation, but I have had my share of guys who are flaky, used me for their rebound, and simply weren't "men." I allowed myself to think they were good enough because my relationship w/my father was always nonexistent. It wasn't until a couple of years ago I was able to find a great guy who truly likes to communicate and be upfront for me to realize what I was missing. I can relate to the pattern/cycle that you're in. It's very difficult to weave oneself out of that.....but I've seen many other people do it, as well as myself. It will take a lot of time--perhaps even seeing a counselor? having someone else to help lift you up can be a big asset--but you're obviously a strong person, so you can do it. It's itty bitty steps.

Cheers to you for reading between the lines with your BF and allowing yourself to see alot of the truth for what it is.