My BF and I have been together 6 months. We're at college and we live in a house share together with my cousin. 3 months ago a new Roommate joined our house share.

Since Roommate moved in, I get on with him pretty well and my BF can be really jealous about it. Like if Roommate and I are talking, my BF often starts picking on Roommate and saying mean things to him (for example, Roommate studies really hard, and my BF is always telling him the reason he has to study so hard is because he's so dumb, which isn't true, Roommate is just hardworking and he's actually very smart).

I don't want to fight with my BF so sometimes I let his remarks go, but sometimes I tell him he shouldn't say things like that because it's just mean, but that only makes my BF meaner to Roommate and mad at me. I don't know why my BF is so jealous. Roommate is a really nice guy and we have a lot in common, but we never hang out one on one or anything.

My BF is also always criticising Roommate's looks because Roommate is quite overweight and my BF is always saying how much better looking he is than Roommate. Yesterday Roommate remembered that I had a big presentation coming up which my BF had forgotten about and I was really touched. My BF got really mad and kept telling Roommate that he was ugly and fat and that he'd never get a GF. I said that was mean and unfair, and my BF got mad and said "Do you find Roommate physically attractive?" and I said it didn't matter what I thought, he shouldn't say things like that anyway. But he kept asking me over and over, so in the end I was honest and said, "yeah I don't think his weight is a problem and I think he has a handsome face".

My BF was absolutely furious and he's barely spoken to me since except to say that I have terrible taste and he doesn't respect me if that's the kind of taste I have, and I betrayed him by saying that in front of Roommate. Even though it's not like I said I thought Roommate was more attractive than my BF, and my BF KEPT asking me.

Now my BF isn't speaking to me at all. Was I wrong to be honest when he kept asking me over and over? I feel like if he didn't want the answer he shouldn't have kept asking me? But I'm also afraid that maybe I was disloyal?

UPDATE: I haven't seen my BF all day and I sent him a message 4 hours ago asking to have a serious talk about our relationship. He's just completely ignored me (left it on read) so as far as I'm concerned I'm done with him.

TL;DR: My BF is jealous of my friendship with our Roommate and kept asking me over and over if I found our Roommate physically attractive so in the end I gave him an honest answer and said yes. Now he won't speak to me and says I'm an asshole. Am I?