wow- long distance relationships... man, am i glad i don't have to do that anymore!
hon, you also have to think about the fact that no matter how much you talk on the phone or on MSN or thru e-mail- there's a LOT lost in the electronic translation. Martel and I used to get upset at each other because we'd read each other's emotions wrong because it's almost impossible to convey yourself properly over IM. so keep that in mind!
alright, so sit down with yourself and ask yourself WHY you feel like you need this guy to shower affection over you. be honest. do you really and truly feel like you're a great girl, in every way, beautiful, smart, sexy? or are there some things you would like to change- ie go to the gym, get a haircut, wear more makeup, stop smoking? if there's little things that you feel insecure about within yourself then you're bound to have those compound into you feeling like your BF isn't paying you enough attention- your own little insecurities keep you from seeing the way things REALLY are! have a heart to heart with yourself- you said you're getting your PhD- which is really time consuming- are you spending enough time with yourself these days? giving yourself a manicure, watching soap operas, going for a walk just because? make sure to show YOURSELF that you love yourself! don't look to another person to fulfill your emotional needs- that leads to dependency and THAT is something which can wear you down faster than anything!
annnd- you said your mother is the type to be dependent and needy. think about that, and think about how you saw your mother doing that. are you exhibiting behavior that reminds you of how your mother acted? like raeanna said, after a while, a relationship gets into a routine. it is in those times of routine that people tend to revert to their subconcious knowledge of how a relationship should be done- so you're acting like your mom, perhaps because that's the only example of a relationship you've ever seen/been exposed to. so, think about what you don't wanna do, and how you don't wanna act, and really think about why you feel the need to do so. perhaps if you think about it, you'll find that there's no real reason behind how you act, just something left over from your mother!
anyway, this is getting kinda long- but i know how you feel... feel free to PM me if you'd like more "IMHO" advice! good luck, and remember, you love him, he loves you, THAT'S WHAT MATTERS!!!