What does it mean when a man says he has a lot of intimate issues to have sex with a girl he's in love with?

I'm a guy and one of my best friends (who is also a guy) told me that he has a lot of intimate issues when it comes to having sex with a girl he's in love with. But he said he doesn't have any intimate issues when he has sex with a girl that he has no emotions for. What exactly does this mean? Does it make any sense? Can someone explain please??