The Creator sets the standards of what is right and what is wrong - whether we fallen human beings like it or not. This also applies to how we should handle our sexual relationships. Thus, His standard is Adam and Eve not Adam and Steve or Madam and Eve.
To reject God's standards is to reject God Himself and those who reject God will be rejected by God with ultimately eternal consequences. Whether or not we interpret that as loving, the fact is that this is what God has revealed about Himself. He is God.