What you need to do is say to him 'I need to talk to you about x. I feel that we never really resolve this issue and it keeps cropping up. I need us to come to an agreement. When is a good time for you?'
Agree a date and time. Make sure it's when you have plenty of time. If necessary, book a babysitter and go somewhere quiet to talk. If he tries to avoid setting a date, be firm. Tell him that you are not happy and you want to firm a date.
Write it down. Both sign it. Make it official. If he tries to change the date, tell him no. There is nothing else that is as important as your relationship. Everything else can wait.
When you have the meeting, set the ground rules. No shouting, no swearing, no storming off. If either of you get angry and need a break, say so. Take a ten minute break then come back together.
No interrupting, no changing the subject, no blaming. If he brings up other topics, just say 'We can talk about that later but right now I want to talk about x'.
Say what you think and how you feel, then ask him to say what he thinks and how he feels. If he doesn't talk, just remain silent and wait for him. If he still doesn't engage, tell him that you cannot resolve this on your own, he needs to contribute. Don't tell him what to do, talk to him about how you can, together, overcome the problem.
He should realise himself that he is treating you unfairly by, in effect, putting you in second place. If he doesn't realise this, you can tell him that, although he might not intend to do this, it is, in fact, happening. Ask him what he will do to change this.
Put all your agreements in writing and sign them. Set another date in two to four weeks time to come together again and discuss how it's working out and follow the same process.
That's how you get him to talk.
If he won't agree to any of this, then he is showing a lack of respect and your relationship is in trouble.
If he agrees to talk but refuses to change his behaviour then that also shows lack of respect and, again, the relationship is probably not going to work unless you are prepared to put up with it like this.