Yeah, I feel you, finding male weight gain games is pretty hard. There’s a few entries in this site that should work but they have furry characters which isn’t everyone’s cup of tea.
In this one you can create your own character with the gender you prefer, so that’s a plus
In this one, all the characters you can fatten up are male, so that’s a plus as well
Finally this one, with some interesting mechanics and pretty good art as well
I know a couple more and I follow their development pretty closely but again, they have furry characters.