I think my husband's friend has a crush on me. What should I do?

This is something I would generally ignore, but his behavior towards me is effecting my husband's friendship with him, esp since he is now our neighbor. When my husband is away he would call me up all the time and want to hang out just the two of us. We have spent whole days together and at 1st I thought.AWESOME! I get along well with my husband's friend. Then out of nowhere he would pick stupid silly fights with me. This behavior was happening often and I thought he hated me for awhile. Then a couple female friends said they think he is attracted to me, but is trying to hide it. My husband says "he might be, but why would he? He knows you're married to me." Too embarrassed to ask my male friends as they are mostly his friends too. When he is picking fights with me, he gets really cruel and puts me to tears (our other male friends have snapped at him over it) and when he is being nice it is over the top nice like making me dinner or buying me concert tickets and he is always nice like that when my husband is NOT around! I just want us all to get along! So from an outside male perspective what, if anything, can I do to stop this confusing behavior and still keep all the friendships intact?