Rehearse the conversation you've been avoiding
Pick a scenario, pick who you'll be talking to, and say it out loud. They won't make it easy. Afterwards you get a report on how it went, with quotes from what you actually said.
Parent or parent-in-law
Sibling
Spouse or partner
Adult child
Your scenarios
Write your ownCan't find your conversation? Write your own scenario and describe the person you need to talk to.