Co-parenting w 11yr & 7m old

Long story short, I have an 11 year old and a 6m old with my current partner.

We were 19 & 20 when we had our first, it was toxic and we went to court, was separated for 7years! Rekindled and 3 years later have a 6m old, this has been so rocky esp with our LO, for the past two months he’s been threatening to break up with me and I just about had it. We had a disagreement on the phone where he told me “f you” and hung up. We have not spoke for two days, based off the last disagreements I’m already anticipating another “break up threat” but this time I’m highly considering just separating.

I’m curious how this would work w a 11 & 6m, anyone have advice?

With our 11year old he only had her every other weekend, would it be the same again??? Thank you