Cuckold Husband Rule 2: You must let me fuck and suck anybody I want to.
After all, dear husband, as long as I bring my cum-filled ass and cunt home to you so you can lick and suck it out of my pussy and asshole, the real winner here is you.
Look at it this way, by freeing me to fuck and suck whoever I choose, I will be getting a lot of different pointers on how each man wants his cock sucked and I will get fucked in new and exciting ways. So, I will learn different ways to make you cum.
Just the thought of that makes me horny. I will always be horny and I will always bring you a load of cum home to eat, so that you can remember Rule 1.