That would be doctrinal breaktrough, but the long strings of popes saying whatever they find convenient at the moment tuned the formal requirements for pope to be infallible pretty high. And i won't even mention that whatever cool thing Francis ever said as a pope have exactly zero influence on church reality.
So by "relationships" he just meant "marriage" as church always did? It's clear from the context he is not, since lower there is mentions of "same-sex relationships", not to mention even the word itself suggest any something wider.
I think he's intentionally vague when using the word relationships. The word does not explicitly mean any one thing. But yeah sex within marriage has always been praised in Christianity. It's been a big selling point of marriage in general. I don't see anything in the article to suggest he's explicitly blessed homosexual sex or truly changed any doctrine.
Yeah, if that was taken on a face value then the acceptance of all kinds of extramarital relationships would be a big doctrinal change, but nothing is happening, as i noted in my first post.