opinions..

Okay ladies. I'm going out to CO to start a new life with the man of my dreams..but he wants to be poly. I don't mind it and he says he does care for me, but my biggest fear is that he'll start caring less about me, and more about the other person. I put it in perspective for him and asked how he would feel if I brought another man into the bedroom and he understood. but there has to be boundaries. please help?