I cannot imagine attempting to prevent my husband from driving a car he loves, or doing anything else he enjoys; as long as it doesn't harm him, me, or anyone else, it's not my damn business. He supports me in the same way. We are not eachother's boss, parent, or overlord. We're a partnership.

As long as one is not neglecting relationship and family responsibilities, not being disloyal, and not spending money carelessly, it should not be an issue. Family harmony should not be dependent upon this kind of choice.

Tell the wife it will make you happy, and promise not to neglect other things that need attention to work obsessively on the car. Take it to the mechanic for major issues. Enjoy tinkering in moderation. Everyone's happy!

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Current car:
1982 300D A New Hope! Three-plus tons of China blue steel, rubber, and magic.

Past cars:
1985 300D, Glorious anthracite on black. Gracie. (R.I.P.)
The rest were crappy--including a 1970 Orange Gremlin.