Feeling overwhelmingly protective of girl after sex (not jealousy)

Ey yo. Everytime I sleep with a girl, be it with a fuckfriend, one night stand or a girlfriend, I always feel a massive need to protect her after I’ve reached orgasm (I usually make her come before me). Especially the times I fuck a girl with a bare cock and bust my semen inside her, I feel so incredibly protective. It’s a feeling like no other. I feel totally complete as a male, and I just want to spoon her, hold her strongly in my arms and caress her stomach until we both fall asleep. I feel like I could take on a hundred bears if needed be, just to keep my girl safe.

Is this purely a personal thing, or is it rooted in biology? Why do I love rubbing her stomach so much after sex though? It’s where the womb and ovaries are, so maybe that’s it?

My buddies say that they just wanna roll over and fall asleep after they nut, but that’s not me at all. I feel this strong urge to hold her against me and cradle her tightly in my arms. To feel her heartbeat and breathing. Often that feeling itself makes me so horny I want to go for round two (and three etc). And often we do. But it always ends with me switching into protector mode again.

This is not being possessive, jealous or insecure btw. I comes from a deeper place than that. Hard to explain.

Is this post-sex urge common in us men? Is there a scientific explanation? BTW I’m 19. She’s 16.

EDIT: Age of consent is 16 here in Norway and it’s normal for the girl to be a couple years younger than the boy. It’s only a 3 year age difference.

EDIT: Every time I’m unable to snuggle after sex due to external circumstances, I feel as If I’ve betrayed her somehow. This even goes for hookups and causal sex. Not every girl likes the spooning.