I think your fiance has maturity issues.

No, it's not okay to go verbally off the deep end over all the many things in life that don't go exactly as we would like. Your guy seems to have low tolerance for frustration.

Being berated as you describe must get pretty old. That can really ruin the quality of your life. It is a form of abuse. I'm not sure how you can effectively deal with this. You hitting a surface doesn't sound like a good longterm solution to this toxic behavior. Don't get hung up on trying to decide what diagnosic label to hang on these outbursts. Focus on the behavior. I don't often recommend couples' therapy, but it might be an intervention worth trying for the two of you. Him seeing a therapist by himself probably won't have much impact on his immature tendency to throw fits and blast away at you.

The good news is that, since you describe him as a decent guy, he might be open to making a behavioral change. He is not realizing how he is coming across. He is failing to hear how petulant and obnoxious he sounds.

Maybe see if you could record him when he's throwing a tantrum. Then, when he is all calmed down and not angry, tell him you need him to hear himself. He might be surprised.