Sorry, there is no higher standard of truth and ethics than the word of God and it is cultural suicide to place fallen reason above it. I for one will stand on the word and will not be shamed, shouted or ridiculed off of that one certain revelation of God. The consequences of a sin are not the basis for it to be named a sin, it is sin because it transgress the law/word of God. The temporal consequences are a gracious reminder that the eternal consequences of sin are real and that fallen men need mercy that can only come through the sacrifice of Christ.
Proverbs 3:5 Trust in the LORD with all your heart, And lean not on your own understanding;
Wisdom 13 is in the Roman Catholic Bibles.
You might want to read 1 Timothy 3:15.
You are completely missing the argument.
There are propositions which can only be known by revelation, that is, only proven from Scripture.
There are also propositions which can be proven from Scripture, but can also be proven from right reason without recourse to Scripture. That's not setting reason over Scripture, it's only asserting that some truths can be known even without the light of revelation, and were known before it. And because of that, they impose an obligation of belief and obedience even on people who don't accept, or don't have the opportunity to hear, Christian revelation. The proposition that two men can't marry each other is a fine example of what I'm talking about.
And how do I know this? I know it because the Bible teaches it, in Romans 1:18-21 and 2:13.