Lauryn's Miseducation

Tell me who I need to be / to gain some reciprocity
It's a nutshell summary for a conversation I had with someone close this week. We discussed whether we ever really loved anyone in a romantic way and whether we thought it possible at all (yep, the discussion was positive). The irony of having that discussion set to Al Green aside, it's wasn't lighthearted.
It's something I wonder- whether I've actually romantically loved anyone (I even have moments of doubt about whether I've even been in love). I can't figure out what love really entails. . . it's why the female fugee got a grammy. She outlined misconceptions and the struggles people go through all in the name of different forms of love.
This question is more pointed for me, however, seeing as how I'm a hetero male who lost his mother some time ago. Why do I always go for the emotionally-unavailable girls? Can I no longer emotionally commit to/care for a woman? Was I ever able to? Is this why people say that in your 20s you don't know what you want and aren't ready for major life decisions?
The questions aren't too outlandish. I figure I can love someone; the easy way out is to say that the right person hasn't ever come along (something that I honestly believe). It goes against my theory about emotionally-unavailable girls. . . you know, the one where I like them because I recognize their instability and know it means that things won't work and that I can't blame myself for the shortcoming because it's on them. . . it's easier to blame others that to recognize some internal deficiency. . .but repeated behaviour like this on my part makes me think that maybe I do it subconsciously so I don't have to encounter a situation where I might have to really commit.
I also wonder why it is that the only 'good' relationships I've had in the past revolve around some predetermined and agreed-upon expiry date. . .you know, relationships where one person is leaving or where there's some reason why you both understand things won't work out. In those ones, things go well and I look back upon them fondly. Is my enjoyment of them related to the fact that I know they can't involve commitment?
Then there are the ones where a woman's been willing to commit and has tried to but I can't/have no desire to do it. Were those situations a result of a lack of chemistry or did them emerge from me being incapable of love? In each of the cases I can give reasons why I wasn't into the particular situation and I generally believe that none of those situations were right for me but at what point do I start doubting my own thoughts and considering whether my impressions are the result of some emotionally-dysfunctional consciousness?

At least I'm taking a break from women right now. It stands to reason that if I can't believe I want something meaningful with someone, that I shouldn't seek out that kind of scenario. I suppose physical gratification and casual encounters would still be fine but ultimately I'm doubtful in a belief that two people can engage in something casual/physical without having strings attached or without developing attachment or expectations. . . but then again I hear love's where you least expect it, finding you when you aren't looking.