The more you wrote the more awful he sounds.
No good father or husband would call his wife a slag frequently. Him saying it's depression is just a very feeble excuse. I bet he doesn't call anyone at work a slag.
You are doing your children a disservice bring them up in such a toxic atmosphere. Saying you wait until they are in bed is no excuse - they will have picked up on the atmosphere and hear the name calling.
To say he's good most of the time is just not good enough. He should be good all the time.
You and your children deserve so much better.
You can't imagine being with anyone else because you got together with him when you were barely out of childhood. If you had had more life experience you would know that nice men do not call their wife a slag. He is counting on your inexperience to verbally abuse you. There are thousands of decent men out there who do not and would not refer to their wife and mother of their children as a slag.
At 37 I bet he has slept with many more than 7 women. Double standards?
He sounds vile and I would not want him as a role model to my children.
And as for sleeping with someone younger than you when on a break is creepy. He obviously likes very young women and this would worry me. Eurgh.
Red flags are waving all over the place. Pull up your big girl pants, protect your kids and yourself from this sorry excuse of a man. Raise your bar. You should not put up with this.