@ shield:
Whether or not that is cheating depends on the dynamics of the relationship and what they have agreed between them.
I have a couple of very close female friends who are not my GF, although one is an ex-GF. I spend quite a lot of time with both of them. Well - one of them I see about once a week, and the other 2-3 times a week, but that's actually rather a lot given we all have full-time jobs, the one I see 2-3 times a week is in a committed relationship and has a child... In the case of the second woman (the one I see most often) she sometimes comes round to my house to hang out. We are quite physically affectionate and cuddle sometimes. Her BF is well aware of this and knows I would never go beyond the line - she and I would never kiss on the lips, for example. She does kiss me on the cheek sometimes. Our relationship is deep and close but it's friendly, not sexual. Her BF has even told me I'm pretty much the only guy who could take her out to dinner, or away for an overnight trip, and he'd be totally comfortable knowing he could trust me.
So, if your roommate was in that situation and his partner is comfortable with his friend cuddling him = not cheating. If his partner would be uncomfortable, or is unaware.... possibly cheating.
If he created a clone of himself in an attempt to simultaneously cuddle his friend and his GF, that's multi-accounting and would result in both clones being banned.