How can I become more confident in my relationship and myself despite HUGE changes?

My boyfriend and I have been dating for a year now, we are best friends and in love. He asked me to transfer with him to another college (which is a better move personally for me as well as for us) but I am finding that I can't help but feel like I am putting him under a microscope lately because I want to make the right decision----I've all of a sudden began to question how he looks at other women, how he talks about them, if he'll find someone better than me, I watch his actions towards everyone and even lost sleep over the what-if's.And for what?! All I've done is put a wall up between me and him the last few weeks.

This move is HUGE for me, I feel like its more than just transferring colleges and continuing on like we did before-- its saying yes to a possibility of an actual future together (which he strongly hints from time to time). I want to go into this with confidence, not complete mistrust and fear of other women and his faithfullness to me when he has been nothing but an honest person. What do I do so that I can become more confident in the relationship and myself? Any Advice?