Never, which I don't care. I think relationships are overrated.
There have been I think two guys who said they liked me... Unfortunately for them, I already made up my mind on not liking men by then.
And then there was a girl I liked, but of course the same deal happened. It was pretty awkward... but we remained friends.
If I meet someone I have an strong connection with that can be taken beyond friendship, then that'd be nice. But I don't really care either way.