hidden sins

As I said, Peter (and his wife) are very cautious to hide their sins from family and church, in opposite direction taken by John Baptist when baptizing.
A preacher who is struggling with immorality may keep preaching? I have always thought that a preacher immoral behavior would dirty the Word. I asked myself:
- Should I open something to the church? Let us suppose I know someone killed another man. Should I keep silent to the police? In what basis, a christian should denounce a brother's sin to the church? I have been silent, but is it correct?
Perhaps, I must be silent.
I have just read in Proverbs 10:12:

Hatred stirs up conflict,
    but love covers over all wrongs.

In Hebrew, "cover" may be "hide". Hatred stirs up conflict in a church but love hides all sins. Hatred shows up all sin and love leads to communion.
Peter sinned against his wife who decided to be silent. 
I will live in peace with it.
Let the Lord deal with this problem.

In proverbs 10:18:
Whoever conceals hatred with lying lips
    and spreads slander is a fool.

I am quite sure that the couple, Peter and Helen, hides hatred with lying lips and spreads slander against me. Last year, in Sunday School, for instance, Peter didn't attend to the class avoiding my presence saying he had to take care of his health, but as soon as I was relocated to another class this year, he began to teach there. Isn't he concealing hatred with lying lips? 
Perhaps, I am lying to myself saying that I want to expose Peter in search for holiness when in fact I want revenge due to Peter and Helen's bad behavior. Anyway, let the Lord be my shield. I won't expose him; Helen should do it, not me.