Jon should also get to be very very possessive of his son in the reverse incest AU btw. That is his son. He held Elias wholly inside his body for 9 months and held him and raised him and loved him and kept him safe. Elias has been the only person to understand him in a lot of ways and nobody else gets to have him. And a part of himself he can’t bring himself to acknowledge wants to have a part of Elias back inside him again.