Since my Wife has Alzheimer’s I began to guide her up and stand next to her and making sure she received and consumed correctly before receiving myself. (I once found a half of host in her shirt pocket…and it had probably been there soe some months )
From that point on I stayed close and paid particular attention. Now - when we are able to go at all, we sit in the front pew and receive there.
My point is that there may be any number of reasons for couples receiving side-by-side.