WWE's Shawn Michaels and Triple H are probably wrestling's longest-running Heterosexual Life-Partners (16 years and counting). Not that they haven't made us wonder about that first word. They've been enemies, friends, tag-team partners, and gone years without speaking, but they'll be the first to tell you that neither of them has a better friend than the other.
According to Hunter's wife, Stephanie, Shawn is Hunter's "road wife". And read the rest of Hunter's speech, while you're at it - it's proof positive they're it for each other.
Prior to HBK and HHH there was fellow Clique members Scott Hall and Kevin Nash, who first met in WCW when they were put into a faction managed by Diamond Dallas Page (the wrestler that would eventually become Raven was also a member). Hall (in the Razor Ramon gimmick) would help Nash get into the WWF (as Diesel), then the two famously went back to WCW to form the New World Order. Nash was understandably devastated when Hall passed away from a blood clot in 2022, and he commented that he spent more with Hall than anyone else in his entire life.
Sean Waltman, the fifth member of the Clique, has this sort of relationship with Nash and was probably even closer to Hall before Hall died.
Second place probably goes to Kevin Owens and Sami Zayn, who both came up together in Quebec and have been basically inseparable ever since. Not only are they like brothers off camera but pretty much everything one of them has done on camera has somehow involved the other. If they're not tag team partnersnote They would win the WWE Unified Tag Team Championship at WrestleMania 39 they're probably feuding with each other, and tearing the house down every night.
Matt Hardy and Jeff Hardy. Yes, they're brothers, but they're also a lot closer than most brothers their age would be...living within line of sight of each other, doing a webshow together, going out together, etc. They've built up a pretty substantial group of True Companions around themselves as well, with the rest of the OMEGA crew in close proximity.
And from TNA, we have the Motor City Machine Guns, who have used this exact phrase (specifically, Alex Shelley in regards to Chris Sabin) to describe each other.
Edge and Christianaren't brothers in real life, as they used to be billed, but they have been best friends since the sixth grade. They went to junior high together, went to high school together, went to college together, trained for wrestling together, broke into the indies together, went into the WWF together...Christian's TNA stint is the first time in their lives they weren't around each other constantly. The second being Edge's retirement. Christian ended up (temporarily) retiring a few years later and they spent the next couple of years doing everything together (including hosting episodes of RAW and SmackDown!), before their bodies healed up enough to let them come out of retirement (Edge in 2020, Christian in 2021). Then they separated for a third time when Christian opted to sign with AEW instead of staying with WWE... until Edge left WWE to work in AEW under his legal name, Adam Copeland, in 2023.
Charlie Haas and Shelton Benjamin, aka The World's Greatest Tag Team, have a very strong bond with each other; in fact, Charlie has said in interviews that, sometimes, he thinks that his deceased brother Russ sent Shelton to him as a replacement.
The Miz and John Morrison definitely qualified during their time as a tag team. When they were separated in the WWE Draft, one announcer even stated "The bromance is over!".
Perhaps the most tragic example is Eddie Guerrero and Chris Benoit, who were together for decades, through New Japan Pro-Wrestling, ECW, WCW and finally WWE. Eddie's death was something Chris never got over, and likely contributed to that fateful weekend in Atlanta. Of the talented trio known as "The Holy Trinity" or "The New Japan 3", only Dean Malenko remains.
CM Punk and Colt Cabana used to be this. Unfortunately, their friendship got completely wrecked in the wake of the Chris Amann lawsuit thanks to a dispute over the legal fees, which culminated in them suing each other. Everything ended up being settled out of court, but the damage was done and not only have they not spoken since then, they refuse to speak of each other at all. Notably, when Punk was signed to AEW one year after Cabana was, the company made no active effort to associate them with each other at all, despite having no issues drawing on everyone else's history together on the indies.
To a lesser extent, Punk and Kofi Kingston, as Punk has outright said that Kofi is his "road wife".
Daffney Unger has called MsChif her better half (half of The Scream Queens, their tag team). MsChif has in turn said she can make Daffney's ASS whole. (Unger was scouting for another member of her All Star Squad).
. And read the rest of Hunter's speech, while you're at it - it's proof positive they're it for each other.