Robert A. Heinlein said this quote

Love is that condition in which the happiness of another person is essential to your own.

~ Robert A. Heinlein

Don't explain computers to laymen. Simpler to explain sex to a virgin.

~ Robert A. Heinlein

Jealousy is a disease, love is a healthy condition. The immature mind often mistakes one for the other, or assumes that the greater the love, the greater the jealousy - in fact, they are almost incompatible; one emotion hardly leaves room for the other.

~ Robert A. Heinlein

May you live as long as you wish and love as long as you live.

~ Robert A. Heinlein