It's none of your business, people can live their lives as they want and the pursuit of happiness is different for all of us.
If it does not harm anyone else, who cares?
But it does harm other people. It may not be physical but peoples rights are heavily affected by it.
I think you need to share more about your thoughts here. How does it affect anyone negatively? How are peoples rights affected negatively by giving more rights to those who are gay/lesbian?