Nothing says "I love you" more than when an ex that was a real jerk to you laments how they are envious of your life and wish they had what you had (good job, stable life, loving relationship, good friends, etc.).
HA!
Well, that and when they tell you they regret what they did to you, realize what a huge mistake it was to let you go, and wish the day would come when you would forgive them and give them another chance, but they know that will never happen, so they just think about you every day and remember how they fucked up.
Yeah, that hits the spot...