Tell him that. [Dodger had all but actually said that's what Ragnar had done. Not that Ivar particularly cared, all it had really done was serve to make his anger into a raging inferno]

And it was just sex with my mother. You went straight back to Lagertha until she got pregnant. [Yeah, he's been waiting to pull that gem out. Ragnar, your future self is not winning you any points with your son right now.] You really don't give a shit about anyone but yourself.