I'm not sure my input on this would be helpful, as I've never been a salesman as such. Pretty much all my jobs have come through recommendations from their friends/family, and so the work was already mine, affordability permitting, and I didn't spoil it by farting*
When I visit them they generally have already decided what they want. I don't know who had the final say in these decisions, and when I'm discussing the work with them I always include both in the discussion, maintaining eye contact between them both, so they both feel that their input is equally valid, which of course it is. I don't know whether this is the way it is done in sales, it's just the way I deal with folk, and (touch wood) I always seem to 'hit it off' with customers
Having said that it's usually the man who does most of the talking, but I think that's probably more to do with men usually having a better understanding of the nuts & bolts of what's involved. I imagine if I was selling 'home' products like carpets, furnishing, kitchens etc., the dynamic would be different.
But my view is that regardless of which spouse appears to be in charge, as long as it's an arrangement they are both happy with, then it's fine.
*We once had a bloke come round selling us life insurance, and as we sat on the sofa while he stood in front of us delivering his pitch he did a fart which was so loud even the cat looked up, and he never broke his stride, just inserted an "Excuse me" into his pitch and carried on. Then he said "Ooh nice speakers, Acoustic Research are they?" He almost made the sale, but unfortunately he had the same whiney voice as the bloke that bullied me when I was an apprentice, so sending him away felt like justice. Poor man.