"My wife said to me, 'Do you spend another three years at Manly or do you go to Parra and have a fresh start'?" he said.
"I'd rather my family [and] me be happy at another club than be miserable and moody for another three years."
Speculation over his future soured this past season with the Sea Eagles as tensions within the club heightened when close mate and fellow veteran Glenn Stewart was not offered a new contract, prompting his off-season move to premiers South Sydney.
"It just wasn't the same place for me any more," he said.
"To save any headache, I thought the best thing ... is to probably walk away."
Watmough said he retained many friends at Manly, including coach Geoff Toovey, and he isn't about to move his home west from the northern beaches where he grew up.
He also insisted he had no second thoughts about a move to Parramatta when Eels superstar Jarryd Hayne left recently to seek an NFL career in the United States.
Instead, a major attraction was playing under Eels coach Brad Arthur, who was an assistant to Toovey at Manly, before returning to the Eels last season and prompting a turnaround in their on-field form.
He declined to comment about the "touchy" subject of his NSW skipper and friend Paul Gallen's recent $50,000 fine for his Twitter abuse of the NRL administration.
While he's now swathed in the Eels' blue jersey, Watmough insisted he hasn't forgotten his roots.
"I'll always be a northern beaches boy," he said.
"[But] I'll embrace everything I can about Parra."
Watmough's signing rounds out a swathe of successful recruitments for Parramatta, with Reece Robinson, Brad Takairangi, Danny Wicks and Richie Fa'aoso also signing.
- AAP
