From Dean's Cards website
"If you will give us the opportunity to earn your business, you will be glad that you did. We guarantee it. We love this hobby and work very hard to insure that orders are shipped 100% correct, mailed within one business day and that the items sent are conservatively graded. If you are not happy for any reason, you may return your order for a full refund".
Your wife may never buy you another card, but the above paragraph from their website would suggest that you had another option.
Giving them the opportunity to earn
my business with their pricing
is another story all together.
As to grading your own cards, I do not have a problem. Unless you are into TPG grading VG commons, grading cards yourself would seem to facilitate inventory management.