James Packer Send Lovey Messages Before Yacht Trip

James Packer was hopelessly in love with Mariah Carey, even giving her his name ... just a month before an ill-fated yacht trip in Greece.

Packer sent emails to Mariah as late as last month, referring to her as MCP -- Mariah Carey Packer -- TMZ has confirmed.

In another email a few weeks earlier, Packer wrote, "I'm in love with you and can't wait to get married and be together forever." He continues, "There's a song I'm listening to now that's got lots of meanings and I hope it makes u smile. When you get caught between the moon and New York City best that you can do is fall in love."

And there's more ... "All my love, laughter, light, respect and appreciation and admiration ... Thank you my fiancee and soulmate." And the subject line reads, "Will U marry me soon MCP pls -:)))))."

And, just a week before getting on the boat on Sept. 14th, Mariah gave James a Cartier wedding band as a birthday present.

TMZ broke the story, Mariah believes everything changed when Packer's right hand guy, Tommy Davis, began questioning his spending and targeting the gifts Mariah got. She insists he was the central figure in ruining their relationship.