WWYD-My DPs best friend is lovely we get on with him well however last year fell out with his girlfriend this was due to ongoing problems with her trying to get between mine and DPs relationship. This girl is now messaging my DPs mum!! We're all adults and I've stated how immature this is. However yesterday I found out she has told DPs mum that she fancies my partner. My partner doesn't know what to do whether to tell his best friend that his girlfriend has been telling people she fancies him or just leave it. Help!!