Hugs to you and your husband. I worked in law enforcement for decades and thank god that there are men and women like him willing to face the ugly things on behalf of the rest of us (I wasn't a first responder--I dealt with the aftermath of many tragedies, though--and I know how deeply people are affected).
Your husband is in good hands, it sounds like. YOU, on the other hand are facing your own (very common and understandable) reaction--denial. No matter how much you wish it weren't so, this thing happened. Your husband didn't choose to be traumatized, nor does anyone choose to become an alcoholic.
One of the analogies I sometimes hear when people resent having to get their own treatment for someone else's "problem" is that it's kind of like being in an accident where the driver responsible doesn't have a scratch but you have broken bones, and insisting to the EMT that the other driver go to the hospital, not you, because HE'S the one who caused it. Whether it's "fair" or not, you have been injured by this. You deserve your own chance to heal. Al-Anon is GREAT--it saved my sanity, I'm convinced.
Yes, your life has been changed. Disasters do that. You can run from it, but the effects will follow you unless you find a way to deal with it.
As mentioned above, you don't HAVE to remain in your marriage. Either partner is free, at any time, to decide that for whatever reason the relationship is not good for him/her. But whether you stay or you go, you take you with you. Facing this now can spare you a lot more agony down the road.
FWIW, my first husband just celebrated 36 years of sobriety. We had a very nice marriage for almost 15 years, and our eventual divorce had nothing to do with alcoholism. We are still good friends to this day. So things are far from hopeless.
The other promising thing about your particular situation is that his alcoholism developed relatively recently. People who drank alcoholically from their youth have a much longer, harder road to get back to "normal." I'm one of those people whose alcoholism developed much later in life. I've been sober for seven years now, and really, to look at my life you'd never know I had a problem with alcohol. I have no desire to drink, and I have a great life.
Hugs, please give yourself a chance to heal.