6 years of cheating means 6 years of him seeing your surprise, hurt, humiliation, anger, disbelief, denial, faking, frustration and disappointment. He obviously is built of the stuff to dish it and take it, he’s okay putting himself before and also against you.
What is the benefit of keeping with him? He won’t change so what does he gain you and your children? Do you have a wonderful home you couldn’t keep without him? Are you dependent on him for reliable transportation to where your job (if you work) would be in jeopardy without him? Are you children completely oblivious to his behaviors? Do your children respect him and think he’s an outstanding father?
Staying with him will tear you down. You’ll have depressions, weight issues, health issues and all of these will invite further scorn from him. Eventually if you give in and stop expecting from him, he’ll blatantly start to demean, despise and torment you. Your children will pick up on this and it will put ingredients into their mix they don’t deserve, things seen, heard and learned that can damage their futures as adults. You will lose friends and family who will start to think you’re “stupid and hopeless”. Get out if you can, don’t let more years go by settling for what’s left of wishing & hoping. Good doesn’t always get rewarded by good.