A lift should not be something she would be concerned about. That is, if your financial situation is squared away. Here's a checklist: 1. Are you out of debt aside from your house? 2. Do you have 3-6 months savings socked away for emergencies? 3. Are you investing 15% of your household income for retirement?
If you can't answer yes to all three questions. You don't need a lift. And I know you don't need a lift because you are afraid to ask your wife for one. Which is a dead give away that you likely can't answer yes to any of my questions.
Look. Toys are fun. But understand you have finite days on this earth and every locker and bumper you buy put you that much farther in bondage to those you owe. Instead of buying a lift right now. Set a budget with your wife. Get yur finances in order. And be able to answer yes to those three questions. Once you can say yes to that, she won't give a flying fart what you spend your money on.