The Kardashians aren't taking 'serial proposer' Rob's engagement to Blac Chyna seriously

The Kardashians have never been shy about flaunting their lives on social media.

So when none of them publicly congratulated Rob Kardashian on his new engagement to Blac Chyna, we were more than a little suspicious. Not even a fake "best wishes" for their brother and Kylie's sometime social media nemesis?

Now, insiders are shedding light on the whole scenario, claiming the family isn't counting on a big, lavish wedding (on or off reality TV) because past experience makes it highly unlikely the engagement will even last.

It turns out the ex-KUWTK star is a bit of a romance addict. Let's take a look at the evidence…

Rob, 29, dated Adrienne Bailon for two years before the pair split in 2009. During that time, they moved in together, got tattoos of each other's names and, according to TMZ, got engaged.

Then came his whirlwind "relationship" with singer Rita Ora, which lasted a meagre three months. Or did it?

Rita, 25, later claimed in a Glamour magazine interview that they were never really a true-blue thing.

"I never thought it was actually a relationship, in all honesty," she said. "I never mentally defined it as 'boyfriend, girlfriend'.

"When I split up with him, I said, 'It's because I'm never there. I don't know how to do it.' That's all I said, then…the rest happened. He obviously felt that creating myths was the way forward."

At the time, Rob took to Twitter to suggest that Rita had slept with "nearly 20 dudes" while they were together.

Make of that mess what you will. But to throw more confusion into the mix, TMZ sources are now claiming that he proposed to her too, although that info never made its way to the tabloids at the time.

Fast forward two years, and Rob has now proposed to Blac, 27, just three months into their relationship. So far, the only person in his extended family unit to comment has been Kylie's boyfriend Tyga.

Awkwardly, Tyga's comments are more concerned about his and Blac's three-year-old son King Cairo  than for his girlfriend's brother. Yep, this is quite the tangled web.

"Everybody deserves 2 be happy," he wrote to Twitter. "What some1 does for their happiness is not my concern, as long as it's not interfering wit my happiness.

"It makes me happy to see the mother of my son happy. My only concern in this situation is my son. I want him in happy environments. He's innocent in this. & I want him to feel as much love as possible."

Do you think Rob Kardashian and Blac Chyna will make it to the altar? Sound off on our Facebook.

Related video: Blac Chyna's huge seven-carat engagement ring...