When Casey Johnson died last week, her and ex-girlfriend Courtenay Semel weren't on the best of terms.

The latter socialite had recently claimed that the 17-carat ring Johnson gave Tila Tequila for their engagement was 1. fake; and 2. the same ring Casey had given Courtenay during their relationship.

Moreover, Semel was the individual that turned Johnson in last November when she was arrested and charged with stealing jewelry, shoes, legal documents and clothing from a British model.

Still, despite these differences - and despite the scathing words Tequila had for Semel just a couple weeks ago - sources say Courtenay is distraught over Johnson's passing.

"Despite the current state of their relationship, Courtenay is devastated," an insider told E! News. "I know their relationship was true love. They were super close and understood each other's socialite background."

Last night, Semel (pictured above with Casey when the pair were dating) Tweeted: "LOVE U CJ FOREVER AND EVER…C U in my dreams X CJS."

Meanwhile, the same source quoted above adds of the former flames:

"They were so in love that they were working on a reality show about their relationship called Love Is in the Heiress. The show didn't end up working out because they broke up."

We're not entirely sure that starring in a reality show is a sign of being in love with each other, or with publicity. But our thoughts are still with those affected by Johnson's tragic death.