Eat less than you can afford, dress no nicer than you can afford, but provide for your wife and children beyond what befits your income.

For they are dependent upon you whereas you are dependent on the One Who spoke and created the world.

Plus, you are granted your entire livelihood on account of your wife.

~ Yevamot 62b, Rambam Sefer HaMada, Hilchos De’os 5:10