It happened with our ex and my wife. They have a TONNE in common, tended to dress very similar. People always tried to attach the "what" to the two of them.
Sorry in my case, it was one of the things that made her uncomfortable. She felt a very sisterly bond to my wife and has broken off the sexual side of the relationship. It was a piece of the discomfort. My wife did not feel the same "creepiness", but it only takes one side to get creeped out
What did I say?...I was vetoed in this case, I was more than willing to be open and tell them...my gf was not...and my wife backed my gf. So I just kept my mouth shut and smiled.