hile A is single, A's marginal tax rate is 15%. When A couples C, A's marginal tax rate grows 28%. The large rise in marginal tax rate does A less fit or ready to work. While B is single, B's marginal tax rate is 25%; when B couples C, his/her marginal tax rate increases lightly to 28%. For couples A C, they are more predisposed to get coupled because they enjoy a flatter average tax rate and pay $4081.5 a year short in federal tax if the status is married. For couples B C, they are succinctly expected to get married or they have less motivation to get wedded because their average tax rate is more eminent and they have to pay $643.5 more a year in federal tax if their status is married. In different terms, if the income received by a spouse is much more eminent than the income received by the opposite spouse, the couple has the motivation to get wedded, if the couple's earnings are almost alike, the tax system presents less motivation for them to get wedded. It indicates that a couple of two high-income earners pay higher taxes if they get wedded. It is