"What shall we say, then? Shall we go on sinning so that grace may increase?" - Romans 6:1
Who said anything about sin increasing the grace God gives to you? Your sin can be whipped clean but don't continue in it because you now have a clean slate. Instead, remember that you cannot serve two masters. You either serve the sin or God. It's either to sin or to God.
Either way you cannot serve sin and be happy. You will continue to want to fill the ache in you that the sine cannot fill. However, serving God fills that ache. It's like you were made to need Him, to be apart of who and what He is. But cannot turn to God only when it's good for you. There will be times where you have to change because God demands change. A human being staying as is, is a being outside the will of God. Personal growth and character is needed no matter if you think you need it or not.