Struggling

Hello everyone this might be kind of long and if you decide to read on and reply thank you

I've been with my current s/o for nearly 2 years now -we were both previously married and he has children from his previous marriage and I do not have any. Over the past few months he has been struggling with his ex-wife over visitation of the children, she's been alienating him and keeping the children away and the way the court system is set in the US getting more time and a comprehensive custody agreement is nearly impossible. He's been struggling with it a lot as have I; my struggle now is not knowing if this is a battle I want to continue fighting with him.

We have disagreements over me caring too much and then he does a 180 and it becomes that I don't care or support him enough. I want to create healthy boundaries and not be too involved with things related to his children since we are not married and I'm honestly afraid to tell him and have been thinking of just breaking off our relationship despite knowing that I do love him and want to be with him. I want to have the conversation with him but I don't even know where to start.

Any advice or kind words will help.