Nothing Good ever comes from trial separations, you're already only giving marriage a trial in the first place instead of committing to it, all that comes from trying a separation IS a separation.
He's not ready or willing to be a parent, or a husband, and you're not willing or ready to see him through to that point.
its frustraiting and its wrong of him. Men dont do this sort of thing. You should let him know that. Men dont put their children after themselves, its what children do. Call it what it is, and then move on.
You cant MAKE him want to be your husband, you cant MAKE him want to be a father. you can whine and moan and carry on and threaten and get nasty and get angry and do whatever else you can to push and shove and try to get him to preform, but its just not going to have the results that you're wanting.
you've got a few options.
Raise the kids yourself with him in the home on his own doing his own thing with no strings attached. He doesnt want to help he doesnt help, but he understands that you're aware that this is what children do, not men. not being nasty, not being a put down, just the truth. Men take care of their children and love their families. What he's doing is wrong, but he's got every right to do those things. he doesnt treat you like garbage in front of the kids, he doesnt lash out at the kids. Period. Thats a rule, if it happens you take those babies out of the house- or call the police to get him out of the house if needed. You dont but up with that sort of thing if he does it.
Raise the kids on your own separated from your husband and collect child support and let the courts work out custody.
Raise those kids together like a functional couple by spending your time on your face blowing snot bubbles in the carpet for your husband who is so incredibly deceived that he thinks he's right- and he's ruining his children in the process and hurting you during all of it.
I come from a line of people who have never separated and never divorced, not on either side as long as we can trace out history back, I've been married 6 years, my parents 27 years, my grandparents over 55, if theres one thing i have been taught its how to not just stick it out, but how to succeed as a pair. IT IS NOT EASY and it does NOT just happen because you're meant to be together- you can get that stupid idea out of your head. Marriage is work, the more work you do the easier the work gets until eventually you're just best friends with the same concept, plan, and direction.
I know its hard, my husband was a jackass the first two years of our marriage, and i almost left him numerous times. He was cruel when I was pregnant, and he stole from me every big moment in a woman's life. my proposal, my wedding, my first positive pregnancy test, and the birth of our son. But through God and prayer and a heaping load of endurance and patience and being brutally honest he's seen what he's done and while he cant fix it he can repent and apologize so we can move on.
You'll get what you want out of your marriage, if you want out of it thats what you'll get. You cant control his will in the situation, but you can let God deal with him. If God's not your cup of tea then you'll have to do your best with what the world has to offer in the form of therapy and counseling.
But for the love of those babies dont allow separation to come in and take away what can be their perfect family.
This is just an encouragement. You can see it through if you're committed to it.