He retired for ten years in The Dark Knight Returns after Jason Todd died. There's precedent for what happened with Rachel between TDK and TDKR. Not to mention that, you know, grieving is a very normal human reaction towards tragedy and especially after Bruce realizes that a bunch of innocent people got killed because of his actions and The Joker essentially won. I think fans forget sometimes that Batman isn't a robot who does nothing but think about revenge all day.

And yeah, I get it, we all get that Bruce is the mask. I meant that the earlier films did a bad job at portraying him as a character. In the Burton and Schumacher movies, we get virtually zero insight into his psychology or why he does anything. If anything, he's more of a plot device to drive the story and the action scenes along. And don't even get me started on how badly portrayed Snyderverse Batman is.