Mariah Carey -- My New BF Doesn't Rock Like Nick

Mariah Carey went solo in Aspen Monday when she walked the streets in her signature red and black XMAS outfit with no one by her side.

Mariah and Nick Cannon were a staple in the ritzy mountain community, always wearing matching getups during the season.

It appears Mariah's new man, James Packer -- who is with her in Aspen -- isn't a fan of matchy matchy.