Nick resents his kids (and Kayla). He wishes he was a childless bachelor with 0 responsibilities that was free to snort coke off a Jamaican stripper's cock.
He can't say it directly, but all that seething is because he thinks he doesn't get the live he deserves where he can do whatever he wants all the time. It just bubbles to the surface in the form of these gay complaints.
The Kayla's body's ruined rant, the constant seething about driving kids everywhere, the "I will be us" tattoo (implying that Kayla is useless and Nick is doing both their jobs), constantly saying how great April is but not Kayla, complaining about how his kid's Christmas responsibilities was getting in the way of him having sex, etc
This is 100% Nick's way of expressing how much he hates his family.