Just hang on, the recumbent guys will be along shortly to explain the error of your ways.

Seriously, as mentioned above ^ slight adjustments in saddle tilt or fore/aft adjustments, and seatpost height can make big differences. When I slight, I mean slight. Like a few mm's. 1/4" of height or fore/aft adjustment can be huge. 1/8" of saddle tilt can make all the difference in the world.
But of those, I agree with Lazyass above, I'd start with tilt adjustment.

And FWIW. The idea of sitting in ANY saddle for 2+ hours makes me nervous. Without changing position, standing, taking breaks, I'm convinced my arse will be complaining loudly. I was "in the saddle" for over 4 hours last weekend but I wasn't "in the saddle" that whole time. I will say, my but usually gets a bit sore at around 20 minutes but it usually passes.
I would think on a trainer one would tend to just sit and spin with much less "moving around" as would happen out on the road. But I've never ridden a trainer.

In the end, only you can decide if that particular saddle works for you.