You could spend a lot of time analyzing your past and trying to answer that question. You could also spend a lot of money on counseling to figure it out with a therapist. If you think that's a good use of your resources, then I say “go for it!”
However, if I were you, I'd ask myself a totally different question--one that would move me forward in life. I'd ask a question that would help me get the romantic relationship that I desire. It simply would be: “What specific activities can I do that will help me become more relaxed around men?”
I suspect that you're an introvert like one-third to one-half of the population. The current dating scene can be more than a little intimidating for those of us who fall into that category. Today's popular mating rituals (on-line dating, one-night stands, friends with benefits) are all better suited for extroverts. They're intimidating, scary, and just not enjoyable for those of us who are more introspective.
That's why it's important for you to find activities that let you interact with men in a fun and relaxed way. You want a relationship that builds slowly. Taking a cooking class, learning to play golf, joining a singles group at church, being set up by friends, or going on group dates are all wonderful ideas for meeting people who want something substantial, not superficial.
It's easy, comfortable, safe, and familiar to stay stuck in the past. We can waste a lot of precious time blaming our histories instead of building our futures. There's no doubt that your dad's absence during those years impacted you in some significant ways. Today, though, it's not necessarily the cause of your discomfort with dating. I wish you well with whatever you choose to do and I hope that you find love!