What is the "rule of thumb" when told there are other women your friend is seeing...

Got a male friend. Very cool guy. We have no commitment, yet are good friends. He know's I'm attracted and we've openly discussed that. I know he's attracted or else he wouldn't call or spend time. He enjoys being single. He told me there are a couple of other women he is friends with too. My question to all of you is how should a woman act, knowing she has to share a guy she wishes would make a commitment? What is the best approach? There are 5 kids between us (he-3 & me-2 & they all get along). What do you do to get the edge, so-to-speak, on getting a guy to notice you above the other 2 prospects? What is it a guy looks for in a woman to want to make that commitment with her when he's enjoying the single life? I can't fault him for seeing others, as I'm not involved. I just don't know how to share him.