Since you are in WT+, your Partner will be in either 'E' or 'F' and the Aisle seats are 'D' or 'F' respectively.
Unless it is the Bulkhead seats, you should be able to convince the the person in 'D' or 'G' to swap with you.
As suggested try changing it when Online Check in opens 24 Hours before. You should be able to get two seats together.