Jason hates Clark Kent. There is no hiding it—not anymore. Out of all the lovers Bruce has had, Jason would prefer literally any of them but Clark.
Any former lover who's willing to get back with Bruce, Jason's calling/texting them, trying to persuade them to get in-between Bruce and Clark, trying to sabotage the courtship between the two.
Imagine Clark is over at the Manor, having lunch with Bruce and Jason walks in with Selina, laughing and chatting happily and suddenly they're joining the two for lunch.
As much as Selina wants to get back with Bruce, she's mostly there for the chaos Jason promised her. The corner of Superman's eye twitching, lips tightening in annoyance and the petty grin on Jason's face with the bonus of Bruce's pretty face? Selina will say it was all worth her time. Getting to have a spat with Superman was also very fun.
Or how about that one time when Jason was attending a gala with Bruce and Clark was assigned to cover the event? Coincidentally, Talia Al Ghul is also in attendance with a gorgeous green gown, hair perfect, and face radiant.
There's no ill-will between the former spouses and Bruce obligatorily dances with Talia. Damian thought his parents were getting back together and Dick almost had a heart attack at the thought.
Clark won't lie, he felt himself shrink at that. What can he offer when he's matched up with the woman who gave Bruce a child? And also happens to have been married to him at some point? It was easier with Selina, the ex-fiancee, but fuck! The ex-wife?? Clark couldn't bring himself to come close to Bruce that night. Bruce felt bad, of course.
Jason keeps bringing back past lovers; trying to show his mother about the several other options he has. His siblings are confused—because what's wrong with Clark? He's nice, he loves their mom a lot, they think Jason is being petty—Dick especially. Tim and Cass are amused, Steph and Duke are all in for the chaos, Damian didn't like that Jason used his mother for his petty tricks, but he does share Jason's sentiment that Clark doesn't deserve their mother—nobody deserves their mother.
But eventually, someone hears of Jason's plot to drive Clark away—who is much too persistent—and decides to have fun with it and join him in his crusade of sabotage.
In comes Minkhoa Khan. He's in Gotham, and instead of staying at the Penthouse, he's made himself at home at the Manor. None of the kids like him—hell, not even Jason likes him. But Khoa doesn't care because the moment he appears, Bruce who was once so sure of Clark Kent, suddenly isn't anymore.
Jason sees this and goes, "You know what? Fuck it." and collaborates with Khoa. So far, Clark has been able to withstand Selina, he pushed through even after Talia's appearance after much reassurance from Bruce, Harvey wasn't much of a threat. But Minkhoa Khan? Ghost-Maker? The man who made Bruce want to extend his training just so he could keep talking to this guy? The man who many people acknowledged, was perfect for Bruce?
Suddenly every ounce of insecurity Clark thought was gone, is back again. The only thing that Clark is holding to is that Khoa wants Gotham destroyed, and thus Bruce can't choose him. But what if he changes his mind?
I imagine this would hurt even more in an Omegaverse AU. Because Clark doesn't have a second gender—whereas Khoa is a Dominant Alpha. Biologically, Bruce and Khoa would've been the perfect match. Equally matched in intellect, skills, and strength, the only thing is that Khoa won't bond with Bruce.
Khoa thinks it'd be too cruel to Bruce because he would always be gone, he can't tie himself to Gotham for Bruce, hell, he doesn't even want Gotham to stay standing.