First question is have you been hinting about purchasing a quad? When I'm thinking about purchasing big boy toys I start a year in advance so she is ready when I find a good deal or buy new. Married for 35 years.
If so use the well dear this is a very good deal you know I've been looking for awhile and this is the best price I've found, I can take the kids for rides outside instead of them sitting inside and that will give her a break from them.
If you want to get a divorce or you don't want her to talk to you just go and buy the quad without her knowing.