My MIL and her family are Hispanic and nooooooo. No no no. My in laws are very physically affectionate, greeting me with a hug (and often cheek kisses from the women, which I return since I was raised in another country where that is common)
But this crazy, disgusting jocasta stuff is in another league entirely. I've never seen anything so inappropriate, or women competing with their sons girlfriends.
The good thing is that your SO is starting to see all this, but I hope he doesn't continue to feel that this comes from his culture, that would be a shame.
To be fair I have heard accounts of overly attached Hispanic families from friends and acquaintances, but I think it could happen in any cultural setting, it's just easier to hide in some societies, if that makes sense?