Another straw man. No one claimed the US Constitution defined marriage. The Constitution does say rights not specified are reserved for the states. If the people in MA want gay marriage, let 'em have it. But the people in my state voted over 80% to define marriage as between one man and one woman.
And this is where the Federal government gets involved. To end disputes between states. If one state recognizes a gay couple's marriage then every state must recognize that gay couples marriage. That is how it works for heterosexuals, so equality under the law states that this is how it must be for homosexual and lesbian couples, too. A heterosexual couple who gets drunk in Las Vegas and get married as a joke are legally married in every state. This same right is equally available to everyone, or it is not available to anyone.
The US Federal government cannot pass a Constitutional amendment banning gay marriage or defining "traditional" marriage as between a man and a woman because that is unconstitutional. It infringes on the rights of the homosexual and lesbian citizens, and the First Amendment forbids religious dogma from becoming US law.
Your religion does not have any power over American law. That is your religious fantasy.
Do you want to abolish the First Amendment in order to protect "traditional" marriage?