Mauricio Umansky Kisses New Flame After Sushi Dinner in Aspen

Mauricio Umansky is living up the single life in the middle of his white Christmas ... locking lips with a beautiful blonde in Aspen after a sushi dinner.

The reality television star was spotted out in the celebrity vacation destination Tuesday night ... walking out of Matsuhisa -- a popular Japanese and sushi restaurant.

At his side was a blonde woman, bundled up against the cold ... and, she clearly needed some body heat -- 'cause she burrowed right into Kyle Richards' estranged husband's chiseled frame.

Seems their lips were feelin' frostbitten too ... and, they just needed to tie them up in order to fend off the icy chill.

While Mauricio's been seen gallivanting the globe with model Nikita Kahn, this is a new woman ... an IG model named Klaudia K with whom he was seen at Kemo Sabe, a high-end Western wear store, earlier in the day.

As you know ... Kyle and Mauricio split last year -- though they haven't officially started the divorce process yet. Kyle stopped by "Watch What Happens Live" last night -- where she shocked Andy Cohen and the audience by claiming a conversation about divorce had yet to come up.

KR says she and MU are just living separate lives at this point ... so, they haven't sat down to talk about formally splitting just yet.

That said, Kyle's taken a few shots at Mauricio recently ... including on last night's episode of "The Real Housewives of Beverly Hills" -- where she agreed he was "probably" going through a midlife crisis.

Mauricio's been spotted with other famous women in the past year and a half ... including his "Dancing with the Stars" partner Emma Slater -- though the two always denied dating.