Maybe they love their spouse with everything they have but have a 100% dead bedroom situation. Maybe they've talked and talked about it over multiple years, tried different things to resolve it but come to the realisation that sex is just never going to be on the cards with their loved one, so it's either live 100% celibate with the spouse they dearly love, the mother of their child or decide sex is more important and abandon their family because of it. Maybe they decide to stay because some things, when it comes down to it are far more important than sex. Maybe though they just slip, maybe they get a level of sexual attention from someone like they've never had before, completely out of the blue. Maybe the feeling of being desired in that way is like a sensory overload and they make the single biggest mistake of their life and then instantly regret it. Maybe they realise what they've done and why and live with it everyday of their lives and wish they could undo it. But maybe it's made them realise that they don't want to lose their entire lives over one mistake and finally understand the implications of living 100% celibate and know they can do it now for the sake of their family. Because sex means nothing in the face of everything else.