"I feel like I'm one of the luckiest players to have played the game - to have the things that have happened to me collectively and as an individual but sometimes there's more to life than football," Cronk said.
"I'm jealous of the guys who have their families here, that have their football and loved ones in the same city."
In 2016, Rushton encouraged Cronk to sign a contract extension with Melbourne to remain a one-club player, but he put in an exit clause after one year in case his feelings changed.
The 33-year-old said it was time to put someone else first.
"We've had thousands of discussions about the possibilities," Cronk said.
"She's (Tara) worked really hard to get where she is and I'm not about to ask her or force her to give up what she's worked so hard for.
"I think I'm in the position to sacrifice and I'm more than willing to do that for our relationship."
Bellamy said he was shocked that Cronk would choose to walk away, but understood his predicament.
"You know it's going to be happening as these guys aren't getting younger but when Cooper told me I was still a bit surprised.
"The contribution that he's made to this club over a long time, we've got to be very sympathetic to that."
While NRL number crunchers in Sydney got to work on how to lure one of the game's best-ever halfbacks, Cronk said he hadn't really thought about facing Melbourne and admitted he wrestled with retiring altogether.
It's not just the club that he's leaving but some of his best mates, including Storm skipper Cameron Smith.
Their history goes back to teenage years, when Smith would drive the unlicensed Cronk to training at Brisbane Norths.
"I feel physically and mentally able to play for another couple of years but there's a lot to weigh up," Cronk said.
"There's my attachment to this football club for one thing; the other thing is once you're retired you're a long time retired.
"I don't have a timeline to make that decision."
