I've been married a long time too. I'd add:
You're guilty.
Even if you have absolutely no idea what you might have done, accept the fact that you're guilty anyway. Y'know how Catholics have this idea of original sin, that the moment you draw breath you're a sinner even if you haven't had a chance to do anything wrong yet? It's like that. The moment she slipped that ring on your finger, everything became your fault.
I've defused many an argument simply by issuing a 'mea culpa.' Half the time I haven't a clue WHAT was my fault, but that doesn't matter. Never let something as silly as the truth as you see it get in the way of killing an argument before it starts.
That one concept more than any other has kept me reasonably happily married for 19 years.