Uhm, if you are married and have syphilis, then only you and your wife will have it. If you cannot get married and have syphilis, you polygamous love life will spread syphilis far and wide.
See why marriage might be better?
"Married" homosexual couples, for the most part, still scoff at monogamy. I have seen this countless times in their own writings. Sorry, but that point is moot.
Then you agree that marriage will make it worse? I'd really like to understand that.