It wasn't because he no longer needed to attract the ladies that he let himself go. Kailash reportedly abandoned washing because a priest told him it would help him produce a son.
With seven daughters born since then, he's still waiting for a male heir.
Still waiting? Singh is 65 and his wife is 60. Do you have a sneaking suspicion he just might not want to bathe? Link
Also being a male I may just be completly wrong in thinking that bathing would help in producing a male because I believe being clean, even after married, would give one more chances.
How can his wife is bearing him???
Go take a bath, dear.