How do you know when to separate

My husband and I have been together for 6 years, married for 4. He had hernia surgery a few months into the relationship which resulted in chronic pain. This has basically caused our sex life to not exist unless I try to initiate however that usually ends in rejection. My husband was abused as a child and this has caused some added trauma and he has pretty much just switched off sexually. He uses to deal with that trauma by doing cocaine however he said he stopped before we met. 3 months into the relationship I find out he was still dabbling in cocaine and almost left him. We worked on our marriage and I forgave him for lying about it all these years.

Fast forward to now and we have a baby and recently moved to a new state (where I don't know anyone). Our intimacy has gone worse and it's something he just doesn't care to deal with. This weekend he ended up doing cocaine with a buddy he knows here and I told him if he doesn't go see a therapist to deal with his midlife crisis and childhood trauma that I'm out. He's reached out to a therapist and is waiting on his new insurance to come through.

I've been asking him for month to do this. It really feels like he's just not invested in trying to make this work. I'm incredibly lonely and after years of rejection when trying to be intimate my self esteem is aweful. He is an amazing father to our son and I don't believe in divorce. I'm at the end of my rope though.

How do you know when you should suggest a separation? If you've been through one, did it work out and you got back together?