That, which you can not stop thinking and talking about
as the mind is just on repeat, repetitive mantras, uttered a thousand times, re-mind-ing yourself of that which needs no reminding of at all, of you loving, losing all truth and value as we bla and blah. When the phrase I love you, becomes a religion all by itself, a religious practice for happy hormones, dopamine, as you soothe your way through life, pretending to love someone.
You may want to try some meditative therapy: https://www.osho.com/osho-multiversity/meditative-therapies/osho-mystic-rose