Lyric discussion by lhoggy 

Cover art for Sick Love lyrics by Red Hot Chili Peppers

The "sick love" refers to how many people feel about the relationship between a 50 year old man and a girl around 20.

I particularly like the lyrics "Rivers get connected so much stronger than expected" and "Your heart is stronger than your head". He knows it's far from an ideal relationship, but he can't help it, they've got too strong a connection for them to ignore it.