I'd say its just stress from lack of sleep and no alone time. Happened to me and my hubby when our baby was smaller. When the kids are small (I have 2 kids - 5yrs, and 1yr) things are tense!
I also stay at home with the kids while he goes out and works two jobs, so I know what you mean! I'll...
I think the judge will probably consider you a douche bag for being so sexually irresponsible.
He'll probably want to teach you a lesson. No really, it usually goes based on your income. Usually around 20%. But every case is different, so I would contact a lawyer. And by all means STOP HAVING...