If you love him and trust him, you can share everything - your dreams, your hopes, your fears. Don't "confront" him, you will only put him on the defensive. You need to start some honest communication, without that, there can be no lasting relationship. He is probably not a good mind reader, and he won't know your inner thoughts and feelings unless you are willing to share... 
Chances are, he loves you a lot more than you realize. 
Also, face the facts. A lot of girls chase after men who are already taken, so your boyfriend is going to face some temptations. And so are you. These dreams are telling you about his temptations. Does he think you are running around with other guys? Those are the kinds of things you need to talk about at some point.
If nothing else, your dreams are telling you you need to talk to him about these issues. Don't be afraid of the truth, and don't let that stop you from communicating.