Everything we do has a consequence to it. It can either be a positive or a negative consequence. I have done some horrible things in my short lifetime which I have apologized for over and over but it doesn't change the fact that I will have consequences for it for a long time.
God will and does forgive us for our sins. This doesn't mean that when we sin and ask forgiveness that there are no consequences for our sin. We still will have consequences for our actions. Consider David from the old testament, he did some horrible things. God forgave him yet he still had consequences for his actions. The things that David did, didn't mean that God couldn't use him in powerful ways. God used David in mighty and powerful ways.
The Apostle Paul is another great example. He was a horrible persecutor of Christians. But God was able to use him in a powerful way.
I guess what I am trying to say here is that even though we may do horrible things, we have to allow the consequences to run its course. A lot of good can come out of horrible situation if you allow God to take control of the situation.
My hope is that God uses me a sliver of how He used Paul and David.