So, you like the middle seat? I hate it. Don't see why i should pick it months in advance when the plane was wide open. I pick the seat I like. It so happened we did end up with a free middle seat, but it wasn't on the list of why we picked our seats. And, i even briefly considered buying the middle seat, but we decided that wasn't really important.
If we're AB or AC, there will still be a stranger sitting with us in a row of three. Its how plane travel works.
If you need a stranger to sit between you and your spouse I'm all for it.