Are you aware the comic book the long Halloween had a romance angle between Batman and Catwoman in it. If you missed that angle, I suggest you read it again as Bruce and Selina are dating in the comic and don’t break up the first time until dark victory. With Batman, rogues gallery, his comics are going to stay dark no matter. The biggest change so far in the film is that Selina Knows Bruce is Batman. This was influenced by batman vol 3 # 50, where Holly Robertson reveals Selina Kyle always knew Bruce Wayne is Batman. also the romance between Batman and Catwoman literally goes back to her first appearance in Batman vol 1 # 1 back in March 1940, when Batman lets Catwoman escape after he and Robin capture her.
I suppose you also want Dick Grayson, Jason Todd, Tim Drake, Damian Wayne Cassandra Cane, Stephine brown, Kate Kane, Helena Bertinelli, Duke Tomas, Ace the bat hound, Tidus (Damian’s dog), and Alfred the Cat all to die as well. That way, Bruce can really be unhappy…or go crazy and destroy the universe.
But to say Bruce is not allowed to be happy is literally an insult to the greatest of DC’s hero’s Batman is the hero that gets attacked psychologically every 5-10 issues, physically Injured almost constantly, emotionally tortured every 30 or so issues. He has found his sons hung from the roof of the Batcave, has held the dead body of two of his sons, had to watch a woman he considered a daughter (and really should be his freakin daughter by now) paralyzed from the waist down, and has found the corpse of the man he considered his father, and had to rebury the man twice. Had his heart ripped out by the only woman he could and has ever loved because she decided to be selfless and leave him at the alter because of that very reasoning you just gave and had to see that woman with her heart literally ripped out, had to fight his friends and watch his best friend be beaten to death by (the greatest) monster (ever to live), had his back broken three times, been in at least three coma’s, had to fail a boy he considered a son (and later adopted him), Had his memory erased by his friends and saved the universe at least 6 times and the multiverse at least 2 times. And has literally had everything bad to happen to the rest of the DC heroes happen to him. Yet still refuse to kill.
Ya, Batman has earned a bit of happiness.
Want to read something catastrophic that happen to Selina? Go read DC Super-Stars #17, specifically the secret origin of the Huntress.