Would God use a man to be a ruler who had a woman's husband killed so that ruler could then take his wife for his own?
Yes. That was David. And, God turned his heart toward him, loved him, called him the 'apple of his eye' and made him a great king.
God's ways are higher than ours. God said he would use the foolish things of the world to confound the wise.
The world is confounded and does not understand the mercy of God when he gives it. I'll never comprehend why he extended so much mercy to me.
It's enough to trust, believe and know that he has. And, THAT...is real peace.