Both the UK resident and the applicant who want to join them in the UK must meet certain requirements established by the UK Immigration Authorities in order to be eligible for the UK  spouse visa application. Since British law does not recognize marriages between people under the age of 18, the key requirement for the Spouse visa is that both the resident and the applicant be over 18.

The additional requirements are as follows:

You must join someone who is a British citizen.

In the UK, your marriage or civil partnership must be accepted.

When you apply, your relationship must be at least two years old.