If you e-filed your original 2022 return you should be able to e-file the amended return. You do not have to mail your W-2 with it.
Your boyfriend will have to file by mail in any case.
IMPORTANT - You said you filed as married. It's not clear whether you filed as married filing jointly or as married filing separately. If you filed as married filing jointly you MUST file your amended return immediately, in spite of what VolvoGirl said. After Tuesday, April 18, you are not allowed to change from married filing jointly to single or any other filing status by simply filing an amended return. After the April 18 filing deadline, changing from a joint return to any other filing status becomes a much more involved process, and you would almost certainly need professional help. If you get into that situation, your boyfriend should not file his tax return because it will have to be included in the process of changing from married filing jointly.
If you filed as married filing separately you should follow VolvoGirl's advice and wait until your original return has been processed before you file the amended return.
(Note to anyone reading this answer in future years: The April 18 deadline is specifically for 2022 tax returns being filed in 2023. In most years the filing deadline is April 15.)
