New Mattress Needed; Opinions/Advice Sought

Our somewhat high-end Serta/Sealy has been in service for 13 years now, and it's showing its age.  Time for a new mattress.  So we finally went out to a store or two and draped our Greek-god bodies across all manner of conventional and foam mattresses.  The leader at this point is the Tempur-Pedic, either Classic or Bellafina (probably Classic).  We're getting a reasonably good deal, so don't warn me about the price.

Sleeper One is male, 185 pounds, back sleeper but likes to dabble in side-sleeping and will infrequently resort to stomach-sleeping.  Wears little in bed (ask Campy), doesn't require very much in the way of bed linens, generates above-average body heat but does not himself complain of in-bed heat issues.  Enjoys the sleep of either the innocent or the dead -- not perturbed by anything once out.

Sleeper Two is female, about 125 pounds, incorrigible side-sleeper.  Wears jammies (summer- or winter-weight, depending), must have topsheet and blanket/bedspread on-board ("covers" pressure is a requirement for sleep), steals body heat from Sleeper One, is herself sensitive to temperature.  Wakes at least somewhat when Sleeper One moves, rolls over, or arrives/departs bed; not enough to be awake, but somewhat rousing.

Specific questions:
1. Any recommendations as to mattress construction/brand/type?

2. As to Tempur-Pedics, I'm reading a lot about the foam getting unacceptably softer maybe 2-3 years out.  This phenomenon occurs in a non-warrantied manner, so you're basically stuck with your spendy bed, like it or not.  Anyone here have a foam bed, TP or other brand, long enough to speak to this issue?

3. We're willing to spend this amount for a mattress that'll give us ten+ years of good service.  If a TP won't, though, I'm happy to buy a good mattress that gives five years ... and then replace it five years out, repeating as necessary.  Not sure how the calculus comes out as to buying a middle-range bed every five years v. a TP for [however long it will last] ... thoughts on that strategy?

4. Other.

And don't think it went unnoticed that any mention of ****ual performance and or frequency was a glaring and obvious omission on your part.

funny enough, I was thinking of getting a new mattress soon too

anyone ever used a latex mattress?

From what I remember lennyquai is some sort of mattress expert/guru.

what do you mean

ahhhhhh   probably not if enough uses are found

I got three years of that action.  Then the boy was born.