Bruce had dealt with countless of possibly near-world-ending threats with the Justice League, on top of fighting against the rogues and lunatices of Gotham City on a daily basis.
And yet, nothing could have prepared him for seeing his kid- whom he had found all those years ago, scared and orphaned- sharing the first dance with their spouse after the ceramony. The venue you had picked out, of course, was paid by him, but Dick had taken over the decorating part.
Seeing you, all grown up and in the arms of your beloved, makes him feel a warmth in his chest he couldn't describe in words. When you had first introduced your partner to the family, he had taken it upon himself to run every possible background check there is. Although he was reluctant to trust at first (as usual, really), he had seen how you seemed to glow whenever you came back from a date.
And what kind of father would he be, if he didn't allow his child the smallest amount of happiness in their already chaotic lives?
When the first dance is over, you walk over to the your designated seat at the table, to drink something. He takes the opportunity, "You look dashing, sweetheart. Are you happy?" The fact that he doesn't just mean the venue, or the ceramony hangs in the air between you, and he knows you would pick up on it. Therefore, he watches you closely.