Sometimes the best thing you can do is to simply walk away and leave it alone.
Don't try to change that person nor the problem. Instead, focus your time and energy on the person you want to become, and invest your precious few years on this earth into the things that really matter... starting with self-growth.
I've finally learned how to appreciate things UNCHANGED.
I know it sounds odd, but the very thing that hurt me the most, is what fertilized the soil needed for my growth. I never knew I could thrive, experience happiness, and live in peace while under tremendous trials.
I thought my circumstances had to change... that person had to change... that situation had to improve before I could move on in life and live it to the fullest.
I was wrong.
Through lots of prayer and guidance from God, I have learned that it is not my role to pull the thorns from my side by forcing change on others. It is my role to walk forward in love and great humility, and to stay focused on the path marked out for me.