To think that I can change/get rid of this personality trait

[Foreverunsure]

It might be a habit, or call it a personality trait, either way, I am really bad at confrontation.
I can't take confrontation, something inside me just stops me even when I know I'm right, that I'm being wronged, that I need to take a certain step for my own sake... both in important and trivial circumstances.
I just have this need to make sure things never escalate. Even if I have to compromise something I don't want to compromise. The few times I have pushed myself to confront someone, I end up feeling like crap and upset with myself. Now I'm fed up of this. I'm in my 40s and it's ridiculous. I just get angry inside, and then those around me struggle to understand why I'm in such grumpy mood.
Is it unreasonable to think that I can change this, even though this is who I've been my whole life? And how? practice?

Well, you could have quietly said "Just keep your voice down, otherwise you might wake the kids." and perhaps offered to help him look for it.

It's difficult to advise on the shop exchange, as it depends why you're exchanging it, but if it's because it's faulty or something, then assertiveness training should help you there.

You need to build up your self esteem. Your opinions are as valid as anybody else's. Remember, a difference of opinion is not confrontational, and neither is being assertive.

Good luck.

It's OK to let things go. But only if you are actually letting them go. I call it channeling Elsa!

In the case of your DH you clearly needed a different strategy because of the crying.

Can you elaborate on the shop example?

Where can you find CBT assertive courses? Books?

Perhaps an assertiveness course would help.

You can confront people without being aggressive.

I think often people confuse confrontation with aggression.

However dealing with aggression is a different kettle of fish - still mastering that one myself.

I posted a link to an online assertiveness course below. It's really good. Outlines the differences between passive, assertive, aggressive, and passive-aggressive.