I had this type of relationship with someone that I started dating. It quickly became apparant that I didn't want any more than "friends with benefits" and was even dating other people as well. He understood this although I know he wished for more. I ended up getting married to someone else but we are still extremely good friends. We both know that we can talk to each other about anything at anytime.....so I guess what I'm saying is if he understands the situation then go for it!!! He is an adult and is responsible for his own feelings. If he knows frome the start the situation and agrees to it then it's all good!!