If I was going on honeymoon, I would view the flight to CPT in CW as one of the highlights so I would certainly want to be sitting with my spouse, even if it is an overnight flight and you’ll be sleeping.

Paying to sit together on BA is expensive, but you do it now and guarantee sitting together, or leave it and hope that the passenger next to either one of you is flying solo and is prepared to swap. Club Suites are far better than the old CW so it’s more likely that they would swap but obviously no guarantee.

In this scenario I would pay the extra.