Tell him 2 are better than 1 when it comes to cats. They groom each other and keep each other company. It's less work for you, in some ways. If that doesn't work, have you ever read any of the Sweet Potato Queens books by Jill Conner Browne? They have a "secret" to get any man to do anything you want, but I'm NOT printing it here because this is a family site, LOL. https://www.amazon.com/Sweet-Potato-Queens-Book-Love/dp/0609804138
How to get a man to do anything you want (the answer lies within):
https://www.amazon.com/Sweet-Potato-Queens-Book-Love/dp/0609804138