I am gay and I also did a partnership registration with my swiss partner 2 and half years ago. I receive a yearly B permit which needs to be renew every year, perhaps I am from a non EU country.
I have read in this
www.bfm.admin.ch about Naturalization, "I am a foreigner and married to a Swiss citizen. How can I apply for naturalisation?
You must have lived in a stable marriage with your spouse for at least three years, have lived in Switzerland for five years all in all, the last twelve months of which must be without interruption."
It was not written clearly that it appies just for nornal couples, or for same sex marriage as well, so I consider it is for both cases
So let say after five years living in Switzerland u can apply for that. I have a Thai gay friend who become swiss already after a few years living with his partner. So, if u qualify those conditions, give a try.