I have a house with a friend for several years now. I think he's attractive but definitely not in a romantic sense. He is absolutely not in love with me so this is nothing that could hurt him. It doesn't hurt him either as I would be delighted if he found a nice girlfriend.
But it's been only this year that I have tolerated some sexual activity because I wanted to chat. I'm not outgoing but I do like chatting!
It's best to talk to him about it really so that we're absolutely clear? I think he knows that I'm fine with messing around a little when I'm in a talkative mood. Definitely not full sex. It is a complete trade off really!