I just had a problem where my spouse made the reservation, added my hhonors number, and now I'm not getting credit for the stay. Even though I was on the reservation as an additional guest, and I paid the bill with my Hilton Hhonors Surpass Amex. It's kind of ridiculous that I go to their website and ask for the credit, and they tell me they won't give it to me because my spouse's name is on the top of the reservation.
So, my recommendation is as follows: Make a decision and decide which of you wants to be the alpha for points and travel discounts. Put all of the accounts that are going to earn and get the best discounts in that person's name, and it will save you a shuh-hit ton of hassles with Hilton later on down the road.