Are you getting married before your passport expires?
If so, you can use it for your honeymoon despite it still being in your maiden name. This happens all the time.
When you book your honeymoon your flight will be in your maiden name and having a different name on your passport will complicate matters.
Alternatively you could change your name to your married name now (by deed poll is easiest) and apply for a new passport in your new name.
But if your passport expires after your marriage, I would leave it.