"What happens if my children are there, and they witness that?"
Then they'll see a fight between two people they love. Never fun, but I dont think there's any reason to think it would be damaging per se, at least not moreso than entirely losing a parent figure. My parents didn't fight much when I was growing up. I have plenty of friends whose parents did, and they're ok. My impression is that it's really problematic for kids to witness emotional or physical abuse, but tension or a fight aren't that. That's just my take though, I'm not a child psychologist, I could be wrong about the impact.
For what it's worth, I believe you've been trying hard to do the right thing, and that there is no good solution from where you stand. I'm sorry.
The major players. Me, 30ish bi female. Gia, girlfriend of 4+ years. Clay, boyfriend/dom. Davis, ex/friend/"it's complicated." Eddie, roommate & fwb.
The supporting cast. Eric, Gia's husband. Bee, Gia and Eric's toddler. Dexter, Gia's lover. Helen, Eric's lover. Izzy and Nikki, Clay's partners. Liam, Eddie's husband.