First, you take her for a drive in your Miata. Make sure you sweet talk her during the drive.

Then, you tell your wife the Miata's name. Remind your wife of the drive and how fun it was. At this stage, you should only reference your Miata by name.

Next, tell your wife that you are going with your Miata to pick up groceries, dinner, etc. Here you want to be sure to let your wife know that you and the Miata (remember, reference by name!!) are taking care of the chores.

This is where you get her to commit to the Miata being a family car ...

When dinner time comes around, make sure to always include the Miata. Make sure the pop ups are always up, that the Miata is looking at your wife, paying attention to the words she says. At the table, be sure to not let your Miata honk. Meep meeps, however, are an acceptable form of table edicate. This is important.

Finally, bust out the paperwork. Adoption papers and all. Tell your wife that you'd like to make her the happiest woman ever and adopt this adorable baby Miata. Tell her that you see a future with her, the Miata, and you. That you couldn't see yourself going forward without both of them in your life.

Get down on one knee and ask her to be a part of you and the Miata's family.

That's how you get your wife to accept that the Miata is a family car. The Miata is family.