This is very strange though - that she is SO determined that Tidy does the decorating.
Unless you're a professional decorator OP - then I think the point she is labouring is that you're not doing what she's telling you is your job.
This is one side of the bridezilla coin...on one hand they feel a huge burden of responsibility in making the day (whatever constitutes a 'day') 'Perfect'. Its literally like being God for a day, in their minds.
On the other hand with being God comes an expectation that everyone will bow to your commands. You're not playing ball, Tidy. She is SPECIAL because she's getting married. You have to recognise this and do ANYTHING (coming from Australia, leaving hospital after a caesarean, without your baby who will no doubt cry, abandoning a sick parent) to make it all happen because it's her special day and this is your chance to be there for her/part of it/etc etc.
If you fail to do these things, you are failing to demonstrate that you care about her AT ALL or will ever be there for her again or ever have been, truly, in the past. She will cry, she will be offended. She will get other people to contact you with whom you have never spoken.
She has, in other words, got it really bad.