I can completely understand where your coming from, My mum remarried a few years back, and my stepdad hated me, so i got stuck in a boarding school for my remaining year and a bit of highschool, with minimal contact with my mum and dad (who lives in a different state), the biggest side effect of this was how close i got to my boyfriend (still soon to be fiance

), I got really clingy, because he was all i had, all i still have. We saw eachother everyday, but it was never enough, and now we are living together, we still miss eachother whenever we go off to work. Its ok to feel clingy on the one person that you trust. But you may want to sit down and talk to him and made sure that its not going to cause any problems, i was lucky because my boy is actually clingier than me (as difficult as that is to believe). The biggest thing that scares a lot of young women is that they rely on one person, and because dependent they actually end up driving them away.
If the clingyness is becoming a problem, try and dispurse it out a bit, become closer to some friends, and cling to your unborn child, because they are always there with you (least till they are born).
Goodluck! hope that helped a little...