I agree with everybody - it's not intended to be cushy, but you should be comfortable. First thing to look at (because it's the least expensive option) is saddle adjustment. Fore/aft, tilt, and height. Experiment over a period of time. If you can't dial it in over the next couple of weeks, then think about getting a new saddle.
A very good option for a 275 pounder is a Brooks B17. I've used one for 8 or 9 months, and it is very comfortable. The B17 is intended for more upright riding positions, which is probably what you're doing on a Trek FX at 275 lbs. When I was 275 it was a godsend. Whatever happens, even if you have to sit on a bed of nails, don't quit riding -
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Trikeman