Jennifer,
If you are the
policyholder, then it's only you who can change details of your policy for car insurance purposes. Your boyfriend is just a named driver on this policy and if he wanted to change something on the policy, then your insurance company will need to speak to you before altering any details on the policy.
Most insurance companies also will charge an administration fee to change the details of a policy once it has been issued and will send another document through the post to reflect the changes which have been made.