Why didn't he stand up for me?

I went out with my fiance last night and some of my girlfriends to have a few drinks and listen to a live band. We were having fun until one of my fiances friends called me a f*ing b**** because I told him not to touch me. My fiance just laughed and acted like it was a joke. I didn't find it very funny I was actually really upset. This happened before too and he called me a f*ing idiot and my fiance again didn't say anything to him. I'm annoyed and upset and didn't sleep at all last night. Why doesn't he stand up for me? Why does he let this guy call me names? I asked him these questions and his response was "It's not even worth fighting over" Please help... because I'm ready to end our relationship because of this. I need a real man who can defend me. Not a wuss.
Why didn't he stand up for me?
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