You are constantly making excuses for yourself about how you can't go no contact, you can't keep him out the house, you can't stop having sex with him.
You can do all of these things, but you are choosing not to. I get why. He's been controlling you for 14 years, so that's your "normal" - that he has all the power and you have none.
But it's not normal, and it's not right.
You don't want him to come into the house? Lock the door. Wait til he knocks then just open the door and send the kids out. If he pushes his way in, call the police. He has a key? Change the locks.
You don't want him phoning you? Block his number. Block withheld numbers (download an app called Blockade which will stop them automatically.) Tell him if he needs to communicate re the kids, he needs to email you. Block him on FB and any other social media.
If you're not having any contact with him then he has no opportunity to try to get back in your knickers.
There's a no contact support thread on the Relationships board somewhere. Join that and reach out for support when you are wavering.
You CAN do this.