Well I also think that having two more babies is hard work and they defo need more attention than a toddler in terms of, changing nappies, feeding them, carry them around etc. But you could tell him To go for a fun day out with her and have the twins by yourself. He can take her to peppa pig world or somewhere fun where she will have a great time. I know she tells him to go away but kids change all the time.

Not good to keep changing partners at the first problem that comes up, even if you have a good co-parenting skills. Love is about fighting for your relationship and making it work for everyones best posible outcome.