My partner smokes weed all day everyday and its tearing us apart.

@HopefulMamaof4

he is an addict .... he may be able to cut down or clean up for short times to appease you but soon will be right back where he is....

unless you leave for good the give an ultimatum each time get less and less effective..... 

whatever the item is an addict only gets better when they see it and decided to quit or change for them not you / kids/ life etc... it is extremely hard to be a partner to because we want then to change for US but that is often only a short term fix.... 

be honest with him say hey we re right back where we were i choose not to live this way ..... so if this is your way of life you will be alone...

Do kids know ?       how would he feel if they did this too?     how would he feel if one or more of them did this but were not functional......... could not hold a job or relationship .......but they think  "i can do it dad did his whole life"   

What sort of bad thing does he need to see his issue....

I've been in your shoes before with my abusive ex-fiancé whom I had a child with. Overtime, his alcoholism and weed addiction became worse. He would just come home, smoke, drink and play videogames all day. Sometimes he would steal my money and car and go out without even calling or texting me when he'll be home and will come back at 3 or 4 in the morning. 

Similar to your ex, he would be sober for a few months than go back to how he was. He increasingly became more violent and tried blackmailing me into staying (I have no friends/family, so it was difficult...).
We've tried couple's counseling, I've tried using "I" statements to better communicate but nothing changed. He was verbally, physically, and financially abusive.

I left him when he nearly ended my life.

It sounds like your ex isn't interested in a relationship with you or his kids to put it bluntly -- I think he just wants a maid, similar to how my ex treated me. Your ex came back when he needed help, not because he wanted to. He wants an easy life.

I'm sorry for being harsh, but...It's best that our kids don't grow up around the other parent who is constantly condescending and treating their spouse poorly. Him being on his videogame all day can make them feel neglected to. Before, when I tried co-parenting with ex-fiancé, he would always cancel his visits last minute and that hurt my son, that I ended up having to cut him COMPLETELY out of my life. I gave that joke of a person too many chances.

Ever since I left my ex and cut him completely out of my life, I found my soulmate who treats me with love, respect, support, and kindness. We're planning on building a life together too.

YOU also deserve love, respect, support, and kindness. This man you're with WILL NOT change. Some addicts are users and manipulators -- I ended up dating a few before I dated my soulmate who is not an addict and treats my son with kindness, despite not being his biological father.

You deserve better. You ARE worthy. You matter. Your feelings matter. He is not treating you fairly and you don't deserve that. There are plenty of fish in the sea who will love both you and your children.

You sound like a lovely, caring, and considerate person. You deserve the same affection.

If your comfortable, would love to hear an update to make sure you're OK.