There is no easy answer, my heart wants a second dog and my head knows, it doesn't make sense.
I've only been a "pet parent" for about 3 months now. I adopted my Havanese Sergio at the age of 2. He weighs about 11 pounds. I bring him with me every where I can. He would much rather be with me than left behind, and he travels well. I just purchased a blue backpack soft sided carrier when I realized I can take him on the Washington D.C. metro rail and bus. He brings smiles everywhere we go!!
My advice to you, and my support, is to not worry so much about it for now. Your other dog hasn't passed yet. Just enjoy being in the moment with your dogs now, and decide what to do later when the time arrives.
I often wonder, no offense, just playing armchair psychologist, if retired people experience empty nest syndrome and to avoid spending more time with their spouses, they want dogs to fill up that void.
Or, maybe they don't realize how much energy Havanese dogs have and how much attention and praise and time they crave from their humans. They think another dog will "entertain" the one they already have.
Please just think about why you want another dog, and make your decision with both your heart and your head.
I think your relationship with your husband is very important, and I don't think sex should be used as a bribe (or food).
This is just my 2 cents. I am neither married, nor an empty nester, nor a parent, so it's just my observations.
Also, I edited this to add, that I don't really know whether you're retired or an empty nester. Havanese seem to be very popular with people who are older and retired. It takes a lot of time to groom Havanese in full coat.