Hi! Now that Valentine's Day is over, I thought you'd like to know something else I saw in Gregory Godek's 1001 Ways To Be Romantic .
"The heart shape we associate with love is a is similar to a mathematical formula r (r=a (1-cosA). It is a 'cardiod' or a pathway of a point if a circle that rotates externally without slipping on another equal circle."
Same as in a healthy relationship, you each have your own lives with good boundaries and resources, and you share energy, time and space without taking over your partner's life.