Thanks for your question. I will try to help.
As you are on a spouse visa your only option to extend is to apply for an extension before your current 2.5 years runs out.
When you do this they will grant you a further 2.5 years to that you can reach 5 years residence (ie. living here) in the UK on your spouse visa. They only extend for 2.5 years, not a further 5 years.
Before the extended 2.5 years expires you can apply for “indefinite leave to remain” which is they right to remain permanently in the UK without applying for any more visas.
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