Immigration rights in Gibraltar

Hello everyone,
Not sure if this is the right place to ask this question but if not hopefully someone here can direct me to the correct place.
I am an American married to a British man (Cival Partnership 10 years, marriage 1 year) married in the UK. We are currently living in Spain but I would really love to get my British citizenship or a BOST citizenship.  Can anyone tell me if this os possible if we moved to Gibraltar and if so what is the procedure? If would be fantastic if I could gain my British citizenship and still be able to live in the sun 😊
We are both retired, I retired from the US military and have a good pension to live off.
Thanks for your help.