The word you may be looking for is 'shield'.
There's a really obvious answer here...Stop hurting him! Even if in reality, you're not, he thinks you are, and that's real to him. So do something to fix it, even if you think it's ridiculous. It means something to him.
hold them tight and say no and keep on doing that and then they will finally know what NO means and theyl stop :)
Retain means to keep something.
To RETAIN something means to keep that something!
it means focus on something
muffle means to keep something quiet or at least quieter than it would be. Silence means to quiet something that is already making a sound.
The term "Pouring salt in an open wound", means that you are causing hurt to something that already hurts. If your ex has hurt you and they keep hurting you and you want them to stop, then yes by all means tell them.
it means you are protected from something
Prevention means to keep something from happening.
No, "keep" is a verb. It means to have or retain possession of something.
sustainability means that you can keep something maintained.
It means if you say you will do something, then DO it.