Sweetie, please pay attention to what Equus has told you.
Meanwhile, here are my additional thoughts on the matter:
You don't "love" this man. You love the man he makes himself out to be when he is lying.
You have three children and you are worried about what will happen to the four of you once you are without this man. That's not love. That's fear and self-preservation.
You need to scrape up your courage and tell him enough is enough.
See an attorney for legal advice about your rights and responsibilities (including child support, visitation, division of property and so on) and then do whatever is necessary to make sure you get that to which you are entitled.
If this man later decides to change his ways and start being honest with you, then you can work at the relationship one small piece at a time - on YOUR terms, and without allowing him to continue to take advantage of you and lie to you.
But that's a pretty big "if" and one I don't think you should plan on.
Take care,
jkgrandma