Threesome advice...

Has anyone ever wanted a threesome when their partner didn't?

So I've had a 3way with a married couple before when I was single... Didn't think I'd enjoy it but it was so hot! I've always wanted to have one with my partner but he always says he's not interested, whether it's another guy or girl. Has anyone ever been in this situation and had their SO change their minds?? I won't pressure him and don't even bring it up anymore, I'm just curious about others experiences.