Christina Aguilera realllllly likes her boyfriend -- and she wants everyone to know it.

The "Voice" mentor and BF Matt Rutler hit the red carpet together last night in L.A., where they were all over each other at the launch party for video game "The Elder Scrolls V: Skyrim."

These two could be in it for the long haul, as X-Tina and Matt started dating right after she filed for divorce over a year ago in October 2010.

Oh yeah ... and once again, she was wearing leggings ... and NOT pants.