PEEING IN BED STILL!??‼️😴

So me and my boyfriend were in bed and next thing u know at 4 o clock in the morning I feel a warm substance dropping down my back, butt and legs and I'm like "oh shit" did I pee on my self or spill my water. 
So I turn around and look under the covers and I'm like I know this Niqqa did not just pee in my god damn bed. I HOPED OUT THE BED AS FAST AS I CAN and I tried to stay calm because I didn't want to embarrass him and I tapped him and was like baby are u okay? And is this an issue? And he was like oh I think it's the sprite and stress so I said okay. Then later on he does it again at his moms house and she confronts me about it. Idk if this is a big deal but... he acts like it's not.
My boyfriend is 21 and I'm 19 and he pees in the bed. Is this Normal!! What should I do?