Is it okay if you know that I'm attracted to my housemates boyfriend?
Are you for real? Oh why do you like your housemate's boyfriend? Tell me this please.
Because he can sometimes look really hot. It makes me feel good to see him.
I think it is normal to be attracted to people. It is what you do with those feelings that matter. You should try not to get involved in your housemate's relationship.
I've never had sex with him. I'm just attracted to him.
Attraction is not really the same as a physical relationship, you are right. Just be sure you can adjust those feelings as long as they stay appropriate. Everyone can have attractions to others outside their relationship, it is how they handle it that matters most.