I'm also about 250, for skinny road bike tires, we need well over 100psi. You need wider tires (and maybe also a bike that can accept wider tires). I'd say 28mm wide at a minimum, but 35 or 42 would be better.

10mi each way is fairly long, especially if you're just dipping your toe in the water. As you say, it will take about 1hr each way -- that's 2hr out of every day. Do you have that much time to spare? It might even take longer if you need to build your fitness up, although that will happen quicker than you might think, you'll make tremendous gains in just a few weeks.

My recommendation: use your current bike, start commuting to work once or twice a week to ramp up. Maybe even drive in the morning with the bike, ride home, ride back the next day, and drive back.

What kind of bike do you have right now anyways? You say "previous bike" -- do you not have it anymore?

The best recommendation I can give is look to spend under $200 on a 90's era rigid-fork mountain bike, tune it up (or have a shop do it) if necessary, and ditch the knobby tires for some slick city tires. Ride that for a while, get hooked, and with the experience under your belt, you'll understand more what you want out of your next bike.