I had a sexual experience with a straight male friend

There is a strong vibe between between myself, a bi guy, and a friend at work who is straight. We always got on really, really well. I always wondered if he was bi as he says he is straight and he has only been with girls before, never a guy. Was wondering cause he's always checking out my package. The other day we were both a bit hungover after a party and and we jacked off together - no touching. He is now riddled with guilt, says he will never do it again, feels disgusted by the experience. Is this normal, or is it just the signs of someone who is bi and now has to come to terms with it? He was very keen to do it - now he says he felt physically sick afterwards. What is going on?