Well, they certainly waste no time getting into the action. "How did this happen"? Well...Hentai.
Normal sex just doesn't do it for him, huh...Man, he has a loving wife who loves him wholeheartedly despite the age gap and...Uh, him not being able to get it up...And then he springs this on her. I almost feel kinda bad for her.
But hey, at least it helped their marriage in the end...! So...All's well that ends well, I suppose.
Figuratively speaking, that turned into a "RUMBLE IN THE JUNGLE!" Well, on the *clears throat* "bright side", it did seem to help Yuki and her husband overcome a temporary block to their sex life .....
Yes i am.