@Endofether the only thing I would add is to ensure you remain entirely calm. Focus on the issue you wish to focus on (I.e not pile in a myriad of other pent up issues if there are any). Be clear, be calm and be very unemotional.
The reason I say that is you then need to watch how he reacts to your approaching this convo in such a way. Does he match your tone and engage/ work with you to get to a compromise.
Or will he be defensive/ start making very emotional / provocative comments. If he starts doing this (which can be common), call him out on what you see. Simply state, I am calm, I am talking about how I feel and trying to find a solution. It feels like you are not in the same place so if you would prefer to reset, we can pick this convo up when you’re ready.
If he doesn’t adjust, stop the conversation and quote literally walk away. Move rooms/ go for a walk/ sit in the garden.
What I have learned with men who have boundary issues with women, is that they don’t immediately like it when a woman calmly enforces her needs/ boundaries. Especially if said boundaries include the message ‘please don’t bring your kids to mine.’ Some men (depending on how dysfunctional their relationships are with other women) will drag that dysfunction into another relationship.
I’m a little less black and white than some of the other posters. No one is perfect as we get older and try to juggle lifes demands / complexities. If your partner can work with you, then that is no bad thing.
Each of us have different limits, and when to call it a day. I split from my exp last year. The split did us both the world of good. I am re engaging from a very different place, I’m much calmer, clearer and resolute. Especially regards my role regards his children and vice versa (I.e I don’t plan on ever having any form of meaningful hands on relationship with his children). Nor do I ever intend sharing my home with them.
If he cannot accept that then I am very content to go it alone without him. Like @LatentPhase, my home is my sanctuary. His dysfunction/ conflict with the mother of his children is nothing to do with me and needs to kept well away from me.
This is my life too. And it really is too short to spent meeting the demands of another man around children that are another woman’s children. Especially when that aforementioned women does not want her children around me.
My biggest fear (pre breaking up with him) was that I would look back in a decade and think I had wasted my life absorbed in conflict and dysfunction. I knew at that point I would rather be alone then have to live this way.
I wish I had had the strength to have direct conversations from a secure place much much sooner.