CORE PURPOSE OF SEX?? "FOR BREEDING OR FOR FUN"

Guys i was a heavily addicted to PMO, porn, and obsessively doing 4-6 times of ejaculation a day... luckily i come to know about this wonderful #NOFAP which not only changes addiction, also changes a person life entirely productive and making ourself better...

as of now ive completed 65 days of NoFap, but recently relapsed, anyhow i rebooted again!..

guys ive been triggering and getting some thoughts of having sex, yes i know it makes us geel good, we do have wide range of sexual arousal and sexual positions and what not!.

but the real thing is, do sex makes us feel lack of motivation or procrastinating?
will it make us obsess?

so whats the core purpose of sex?, just for fun or only for breeding, if its for fun, then why so many people getting spoiled of involving in sex quite often?