Whoa...step away from the ledge dude. I will only speak for myself as a Christian in my response, but I am very confident the vast majority of genuine believers will agree with what I am about to say...
The Church is not coming to take away gay marriage. People have free will to make their own decisions. That includes gay marriage, committing adultery, divorce, lying, and all the other sinful activity you listed. Guess what, I nor the Church is stopping you or preventing you or anyone else from making those choices. But what myself and the Church will not do is affirm behavior that our Creator clearly has indicated is sinful. Won't do it. Don't care if that is the direction society and many churches are headed (affirming same sex relations). God's Word and His character do not change.
But me refusing to affirm sinful behavior (same sex relations) does not mean at all that I will prevent or stop those people who want to make that choice. Nor will I treat them any differently. As Christians, we are just as flawed and sinful as everybody else. But we are still called to show Jesus' love to non believers and help lead them to Christ, as we are all sinners and are in need of a Savior. That includes calling out sinful behavior, not preventing it. There is a huge difference between the two.