Hi weareborgswife.
Welcome back to our Mattress Forum after seven years 
… thus far your husband holds the record for the longest time selecting a mattress.
Thank you for listing the specs of the Arctic Pillowtop from Sapphire’s Sleep site… unfortunately, they do not provide the densities and IFDs of the type of foams used in this mattress. Outside of whether a mattress is a good match for your husband in terms of PPP (Posture and alignment, Pressure relief, and your own Personal preferences) … a mattress is only as good as the quality of the materials inside it so regardless of the name of the manufacturer we’d need to know the specifics of what was inside any mattress you were considering to make any meaningful comments about the quality of the materials (see the article about the Mattress specifications you need to know) to compare the quality of the materials and components against the durability guidelines here . While the coils they use are not the weak link if you can find the specifics of the top 4" of memory foam layers inside their mattress then I’d be happy to make some comments about the quality of the materials inside it or whether it has any obvious weak links in terms of durability.
In addition to this … as you well noted the “no returns policy” is posing its own risks … and also the inability to fine-tune the mattress before/after the purchase in case that your mattress choice doesn’t turn out as well as you hoped for. I’d also be a bit careful with how long a mattress has been on the floor as the floor models can be already well broken in. The ambient temperature in the shop when the mattress was tested sometimes can be an issue as many consumers find that it feels different at home than in the shop. This is because a memory foam would feel firmer or softer depending on the ambient temperature.
Your concern is justified as memory foam tends to sleep hot for those who are sensitive to this and even the newer generation more breathable memory foams are not as breathable or open-celled as other types of foam such as latex or other more temperature-regulating materials. However, the Tencel fabric and the wool/silk blend will mitigate some of this. As mentioned above …even if memory foam feels very firm when it is cooler it will slowly become much softer with heat & pressure of your body over the course of the night.
There is nothing wrong with liking memory foam and if you are committed to it … then the density of the memory foam and the specific type of memory foam becomes important. With weights over 200 lbs … memory foam under 5 lbs won’t hold up nearly as long as higher density/quality memory foam. In addition to this … the different types of memory foam (more or less breathable, more or less responsive, more or less temperature-sensitive etc) and the different layering patterns in the mattress (how thick is the memory foam, what type of support system is under it etc) becomes a major part of how suitable any particular memory foam mattress may be for you. There are some guidelines for purchasing memory foam in post #10 .
I know that after 7 years the prospect of doing some more leg work does not sound very happy but unless you are very lucky with this mattress … all in all, there are too many red flags and things that can go wrong. If you decide to do a hard reset I’d make sure to revisit the most important links in the tutorial are post #2 here about the different ways to choose a suitable mattress (either locally or online) that is the best “match” in terms of “comfort”, firmness, and PPP (Posture and alignment, Pressure relief, and your own Personal preferences) that can help one assess and minimize the risks of making a choice that doesn’t turn out as well as hoped for, and post #13 here about the most important parts of the “value” of a mattress purchase which can help with meaningful quality/value comparisons between mattresses in terms of suitability (how well you will sleep), durability (how long you will sleep well), and the overall value of a mattress compared to other finalists based on all the parts of your personal value equation in post #46 .
Hopefully, with all the data you collected so far you’ll shorten a bit your mattress shopping journey. I’d be curious to know what you ended up deciding
Phoenix