It's been SO long since we've seen Kim and when we spotted her on the road Saturday evening with BFF Brittny Gastineau and Nori and Saint in the back seat, we noticed something interesting ... she's not wearing her wedding ring!

As reports of Kim and Kanye's marriage being on the rocks have flooded headlines since Kanye West's nervous breakdown, we now have our first indication those rumors might be true.

Kim was headed home from sis Kourtney's house around 8pm after having stayed for four hours to celebrate Mason's and Reign's birthdays. But Kanye wasn't there ...

As Kim goes about her daily life, living more cautiously and less flamboyantly than she did pre-robbery, Kanye has separated himself from the family somewhat. He sees the kids, but isn't staying with the family in their Bel Air mansion. He's working on music and working on himself and it appears to be undecided whether he'll re-integrate with the family or not. The ring's off -- all bets are off!