It’s common for people to use avoidance tactics when they don’t want to talk about something. Not talking about these things isn’t going to make them disappear. Putting off conversations can build resentment, making it even harder to address your issues over time.
Accept that it will be hard. But don’t expect that it will go badly, because then it will. Think about the potential positive outcomes as your motivation and guide.
Talk about how you want the conversation to go. You can discuss that if the conversation gets too triggering then you will take a short break, or similar. You can agree to tackle the issue in small bite size segments. Whatever works for both of you. You can also choose to have this conversation with the assistance of a professional.
Have a mindset of respect and vulnerability and your words and tone will match. Be direct and clear in the conversation, without pushing to have your way. You’ve avoided it for so long and now you are finally talking, aim to really address the issue.
What is a conversation that you have been pushing off?