He certainly is a strange looking creature. But in the one picture I've seen of her, his wife KS is actually very attractive, which makes me wonder why he would bother...personally, I never cheated on either of my two ex-wives - or ex-gfs, for that matter - <modsnip>YMMV...I've never understood...
The more I think about it, the more bizarre this whole 'summer house' aspect becomes. Consider:
(1): SE was newly single, so why would she need (or even want) a summer house? Most newly single women would be looking to save money and downsize, not expand into their gardens by commissioning...
I'm surprised nobody's suggested a <modsnip> tryst between MS & JP. If SE had stumbled in on some such shenanigans, it could explain why she ended the engagement. Maybe as a quid pro quo for not ratting MS out to KS, SE demanded MS build her a nice shed, to which he agreed, but signally failed...