Zedsdead.Well done for leaving at long last!Now you just have to hang on in there.
If he is professing love you can tell the police you are being harassed cos you are not interested in him loving you,if it is similar to the UK in the US you can get everything on a legal footing by filing a domestic violence report on him,if he has physically,emotionally,verbally or psychologically abused you in the past then you have grounds.

Don't be tricked by thoughts of he is being so nice now was he ever abusive,he is using every trick in the book to get back with you,it is calculated strategy to win his prey and his prey is you,once he has you trapped again he will turn nasty.Remember how he spent all the money and left you and the kids without and how he wanted you to drive him miles to work even though you were supposedly ending the relationship,tricks to keep you wanting from him and in his orbit.

You need to cut off contact 100%.You know he isn't interested in the kids cos when he rings to speak to them he only speaks to you,it is an excuse to win you over.So don't let him use the kids as an excuse for contact,stop talking to him on the phone,if he wants to see the kids he'll have to go to court for access.Do everything through a solicitor is my advice and start divorce proceedings.

There are lots of books to help you but my advice is go 100% no contact,there is no reason for you to see him or talk to him on the phone,no reason at all!his problems are no longer your concern remember that!

He doesn't care about you or the kids or he wouldn't have spent all that money on himself and left you to go without,remember that,he is just pulling on your heart strings and you are falling for it,well no more,hopefully.
Here is a good source of advice,

https://www.amazon.co.uk/Becoming-Na...e+a+narcissist

Be strong,stand firm,stick to it,he will try make you remove the boundary by laying on the charm,it is a game to him ,a game of control,he has to win it by making you convinced he is right and you are wrong,undermining yourself is what he is going to try and make you do,making you wrong,making you admit it is all your fault, he isn't abusive,he hasn't done anything wrong,he is the victim,you are wrongly accusing him,taking his kids away,for no reason,he will convince you you are the abusive one see.All he is guilty of is loving you hence he professes his love.

It is an act and it is intended to dupe you,don't fall for it the only person this man cares about is the one he sees when he looks in the mirror.Be hard,be tough keep rejecting him,he is a narcissist and he will destroy you if you don't stay away from him.Good luck,Zedsdead you can do this!