he sounds seriously unpleasant from the recent biography, emmie
"an absent father and violent husband, who punched his wife so hard he broke her nose. Johnson Snr is faithless and a creep: in the parched summer of 1976, he told the family’s two au pairs that the water shortage made washing clothes impossible and therefore they would have to follow the lead set by him and his wife and walk around naked, which they duly did. Naturally, Stanley began sleeping with one of the two young women, in full knowledge of his children."
https://www.theguardian.com/books/2020/oct/13/boris-johnson-the-gambler-by-tom-bower-review-the-defining-secret
Other reviews says similar but I haven't read the book itself.