There is nothing wrong in preferring to eat with your significant other or your group. It's one of the great things about cruising. You can be as sociable as you wish. If you want to dine with others you can or you can dine by yourself.
I love cruising. There is something for everyone.
There may not be a 10 top available. You may have to go with two six tops.
Regardless, I would contact the maitre'd as soon as you board and let him know about your situation and what can be done to accommodate you.