Hi happyharris,
You have a number of options when you are part of a couple that have very different needs and preferences. Some mattresses have a design that may be very suitable for both of you and there are also manufacturers that make a “split” layer mattress where each side of the mattress is customized to the needs and preferences of each person all inside a single cover (including queen sizes). There is more about this in the first part of post #2 here.
There are also factory direct manufacturers and some retailers (that have a close relationship to their manufacturer) either online or locally that can build a mattress to any custom size that you wish.
Hopefully you’ve had the chance to read the tutorial post here which has all the basic information, steps, and guidelines that can help you make the best possible choices … and includes a link to the members of this site that sell online and several of these offer split layering in queen sizes (most commonly with latex mattresses) or can build custom sizes. If you let me know your city or zip code I’d also be happy to let you know of any of the better options or possibilities I’m aware of in your area and some of these may have the same option available if your testing indicates that it’s necessary for you.
Phoenix