I agree w/ GermanStar...not communicating the issue was probably more the reason for having your wife pissed off at you...regardless of what stake she had in the agreement. Women are wired differently, so things that we would gloss over might infuriate the significant other.
When my wife and I first got married, we agreed to first discuss anything that involved an asset over $50 changing hands...be it retail, family, or otherwise.
That figure has changed dramatically over the years, but the treaty still applies.
I breached it once when I showed up with a motorcycle for our (then 5-yr old) daughter...I felt the chill for weeks! She later relaxed when she saw the strict safety guidelines I had imposed regarding the use of the bike. Now she is pressuring our daughter to begin to learn other areas of riding...like motocross "stunts"...
...is this the same woman???
Anyway, in your case, women can see through hollow apologies, so make sure you are sincere in the belief that you were wrong in not consulting her first...period. Then accept the badgering you will probably receive afterwards, but NEVER NEVER defend your position, or again, your apology falls flat.
When you are married, you learn to eat a LOT or crow...that's why old married men don't talk much.
