We all teach each other in relationships... the idea is timing it so that positive growth happens.
Also, how we say it, is vital & if we are living what we ask the other person to live.
Marking a moment must  be a conscious loving thing,
an act of caring for someone enough to take on their Karma.
(When ever we call someone on something, we take on their lesson, so we must be able to live what we ask & follow through with them on the resolution of the lesson.)
There is something called: a 3 second scolding that's meant for kids,
yet it actually works for adults as well.
We must wait until something happens, that is obviously off,
and is clearly off enough to explain.
Then, & only then, you respond naturally... if that means screaming or crying...
what ever is honest yet for only one second.
Then, in the next second breath deep, collect ourselves and re-connect with them by honestly telling them how the behavior (not them, so there's no blame toward them) made us feel.
Lastly, in the 3rd second, we ask them what they think would help the situation,
so it won't happen again, involving them in the resolution.
If there is a re-connect established that has deepened the understandings in the relationship the moments have been marked and we can alter behaviors in the future.  Most people will choose love over behaviors, if that love is empowering to their growth and if that is in fact,
clearly what is being offered.