Hi Strumbelina,
Parklane is an invited manufacturing member of this site which means that I believe they are among the best quality and value in the country. I think very highly of them.
In terms of the three mattresses you are looking at … The Riverside is a more traditional innerspring (offset) polyfoam mattress, the Aurora that you have has a polyfoam support core with a mixture of memory foam and latex in the comfort layers and the Breeze has a thinner comfort layer with just the latex and no memory foam. It also says that it has an engineered polyfoam support core (which could mean many things including that it is zoned) which may be different from the Aurora which doesn’t mention “engineered” (but could be the same).
In terms of motion transfer the Aurora with the memory foam would be slightly better than the Breeze which in turn would be better than the Riverside (which has a polyfoam comfort layer and linked coils underneath).
With a weight differential as large as the two of you have it’s not so much that its sagging as it is that your husband is creating a “valley shaped” impression that would extend towards you when he is closer to you. This type of impression is fairly typical of polyfoam base layer because it is not as “point elastic” as a latex base layer although any mattress can do this to some extent depending on the weight difference and on how close to you he is. A pocket coil support core may also be worth considering because compression affects the surrounding area less. Firmer support layers or components will also do this less than softer support layers and the thickness of the comfort layers along with the type of material will also make a difference as well.
I don’t know the specific details of each layer, material, and component they use so I would use your own testing (with both of you on the mattress for at least 15 minutes) to test for this along with their more specific suggestions to see which mattress would be best to prevent “roll together” (as well as the other needs and preferences you have). They are much more knowledgeable and experienced than I am about the specifics of the mattresses they sell.
A “firm” mattress can be many things depending on whether you are talking about the firmness of the comfort layers or the firmness of the support layers or components. Post #15 here (and another post it links to) has more about the different “types” or what I call 'species" of firmness and how they each play a different role in a mattress. In your case you may need some softness in the comfort layers to relieve pressure and isolate motion but you may also need a little more firmness in the support layers underneath or a different type of material or component to reduce “roll together”.
The Breeze may also feel firmer and be more supportive because there is less distance between you and the firmer support layer. For the same reason it may also be a little less pressure relieving because its missing the extra inch of thickness in the comfort layer (the memory foam layer).
Both the Breeze and the Aurora use “plant based” foam which are not really that “eco friendly” but at least are a small step in a good direction. You can read more about them in post #2 here). The Breeze also uses an organic cotton cover.
The main reason that the Breeze feels firmer than the Aurora is that with the inch of memory foam missing in the comfort layer you are 'going through" the comfort layer more and feeling more of the firmer support layer below it. The thickness of a comfort layer is just as an important part of how soft it feels and its pressure relieving qualities as the softness of the comfort layer (and some of the other “specs” that are connected to different types of materials are part of this as well).
My guess is that you may have a similar “roll together” issue because the support layer in both is likely the same (they could confirm this) and you would be sinking into it even more.
If this is an important issue for you I would make sure that you test for this very carefully (with both of you on the mattress for at least 15 minutes fully relaxed, wearing light clothing, and in all your sleeping positions) and this along with their experience and guidance will help you make the best possible choice to minimize the “roll together” that you are experiencing.
Phoenix