You just gotta do it. There really isn't an easy way.
If I may...make sure you go through a sufficient trial period before you go all getting mega attached. Learn about him, his goals, his lifestyle, how he handles stress, how he handles emergencies.
If you've been bit (and especially repetitiously) it's only natural to be fearful about opening up again. There's no magic bullet kind of fix for it, but what works is to expose yourself to it a little over time. As in, open up some (maybe start with letting him know you've had some relationship flops and you'll be slow to open up?) and then when you're comfortable with that level, open up a little more. Then rinse and repeat.
Furthermore, stop putting him on some pedestal. He might be a great person but in the end, he's just a guy and you're just a gal, I'm sure he's vuberable as anyone else.
@epsilon: i'm not saying he's perfect and never makes a mistake never ever. i'm aware he's human and just as capable of hurting me as anyone else. but so far...he hasn't...so that's what i'm focusing on.