The most chilling four words in a relationship:
"We need to talk."
Equally bad is the response is "No you need to talk. I don't have to listen." Then the door slams, or the phone hangs up. Nothing gets said, again and again until the person wanting to say something finally gives up the desire to talk and ends it without the needed discussion.
Way back when, I read or heard that it was healthy for a relationship to leave 3 things unsaid each day. Far too frequently the ex would point out to me that something I told him could have been one of my three . In retrospect that was the worst advice ever. But not discussing issues we drifted apart, and though we tried counseling we were too far entrenched to right the wrong. Maybe let little things go like how the toilet paper is replaced. Hey, the tp is there, if it matters to you it takes 15 seconds to switch it around. The dishwasher is loaded, maybe not to my liking but it is loaded, so you run an extra load per week or so The big stuff needed to be addressed and it never got the attention it needed. So don't be afraid of having tough conversations. How much is that relationship worth to you?
We need to talk:
I've found your porn stash/Ashley Madison acct., etc. you're screwed
I've been having sex with my personal trainer
My mother is moving in this week
I need to whine
I've found Jesus as my Personal Savior
I really thought that I could change you
You really hurt my feelings 2 years ago
I think I'm a lesbian
We need to talk