That's what I was thinking, like they're married and agree to try for a kid and then Percival fucks the hell out of Newt for a few months until they learn he's knocked up. But by then he's kinda used to getting fucked all day every day and Percival would be so rude if he didn't keep it up.
Re: Newt/Graves, adjusting to getting constantly fucked, dub-con, D/s