As for sitting next to a partner, if you don't absolutely need to guarantee it, then you can wait til you get to the airport and ask at the gate if they can move you to be beside each other.
If the plane is totally full you'll be out of luck, but if there's space then the gate agents will happily reassign you.
If the plane is totally full you'll be out of luck, but if there's space then the gate agents will happily reassign you.