John Cena and Nikki Bella Break Up

The 40-year-old Cena proposed to 34-year-old Nikki almost a year ago to the day at Wrestlemania 32.  

Earlier Sunday Cena tweeted out a quote from Walt Whitman ... "Keep your faith always toward the sunshine -- and shadows will fall behind you."  He said the quote is for anyone feeling down.

John may have given a hint of trouble last month, telling Us Weekly, "It takes being able to mesh two lives. I would never ever want Nicole to be in a position where she says 'I'm holding you back from doing this because I feel it's wrong for us.'  And I would never say that to her. That's why she's super busy and sometimes we don't see each other for months at a time, but when we do see each other, it's our time together."