If you want revenge... please read this first

Do not say, "I'll pay you back for this wrong!" Wait for the LORD, and he will deliver you.   Proverbs 20:22 NIV84

Satan wants you to take revenge.  Satan incited the other person to wrong you in the first place and now he is inciting you to retaliate.  They think they're right, you think you're right. And the cycle of retaliation never ends.  Satan's plan is for you two to destroy each other.  Jesus wants to deliver you both from this trap.

Repay no one evil for evil. Have regard for good things in the sight of all men. If it is possible, as much as depends on you, live peaceably with all men. Beloved, do not avenge yourselves, but rather give place to wrath; for it is written, “Vengeance is Mine, I will repay,” says the Lord. Therefore
    “If your enemy is hungry, feed him;
    If he is thirsty, give him a drink;
    For in so doing you will heap coals of fire on his head.”
Do not be overcome by evil, but overcome evil with good.   Romans 12:7-21 NKJV

This is illogical and foolishness from a strictly human perspective.  But God's thoughts are higher than my thoughts and His ways are higher than my ways.  So how do you do it?  It is not necessarily going to feel good, feel natural or be easy to follow God.  Satan will barrage you with "logical" reasons at every turn to stop this foolishness before everybody thinks your nuts.  Your spouse, your best friend, your family, all may not understand.  But if you follow God, He will free you from the trap of revenge, fill you with His love and fill you with the joy of following Him.  And He will start you on an adventure with Him that will never end.

Oh, and the reference to "coals of fire on your enemies head" may mean that your unexpected good will gives your "enemy" no ability to believe satan's lie that you are unjustly against him.  And without that lie your "enemy" must face his own motives and experience the shame of his own actions.  At this point he can convert and become your friend which then frees him also from satan's trap, or he can reject your love for no reason (and experience never ending evil for returning evil for good (see Proverb 17:13)).

God's goal is that everyone loves. Satan's goal is that everyone is destroyed.

What is your goal?