I also think that to use sex appeal you don't need to take off your clothes.
Sex appeal has always been a staple of JT's career, in the unique way he does it: hot choreographies with dancers, theater in the looks and sexy facial expressions he always made.
That only changed a little on the MOTW Tour, so maybe it's fatherhood and not marriage.
On the MOTW Tour the choreographies were less hot and even when he did something sensual, he did it laughing, without the sexy facial expressions that would accompany it.
The only exception was in Filfthy's break dance, he made the biggest dirty face at the end of the choreo while simulating sex or grabbing his dick.