I lost mine 12/15/15. So many of your words--brutally honest, yet tender--could have been mine about my wife/friend/partner. We're blessed to have known such love. You're right. Few men do.
Just get yourself through these days and nights. Don't resent the pain. We wouldn't feel such loss if we hadn't been so blessed. And take heart: healing does come, eventually. Normal--a new normal--quietly rearranges the furniture and makes a home in your head, as will laughter and smiles and true enjoyment.
Laura changed who you are as a man. Don't surrender those changes. Like your kids, you're her living memorial, too. Keep building on the legacy she left you.
But for the moment, the best advice I ever received was: when the tears come, let 'em come! Don't try to "edit" them. Don't try to shut 'em down or hold 'em back. Turn it loose like a TVA dam in spring. Sometimes the tears just seem to rush up from your feet and overwhelm you. Sometimes they tiptoe in, giving you time to "find some privacy." But however and whenever they come, let the tears wash clean your insides. They won't steal your memories; they are your friends for the next couple of years. You'll feel better for it, each time.
Read the little book on the grief process. And determine to read it again once a month, for a couple of years. Each time you'll see new things in old, familiar words. You won't feel so lost. And it'll give you the words to explain yourself to your kids. They will observe and be stronger, wiser adults because of it.
And life is going to surprise you. You may encounter feelings of infatuation for someone much, MUCH sooner than you'd have ever thought possible. If it happens, don't lean into it--slam your feet on the brakes! Unless she's been a close and special friend for years before, only a troubled, insecure woman is going to go after a man when he's vulnerable and susceptible.
After a few months, you may feel like you've entered your second adolescence. And that's accurate. "Who am I, now that I'm not Laura's husband?" In many ways, you really are starting over. Who have you been becoming since you met Laura and became a father? There's a lot of self-discovery waiting for you. You'll begin to remember and question things about how you grew up. Go with it. Your kids will also benefit.
Just promise yourself you won't take any shortcuts answering that question of who am I. The temptation will be to let someone else tell you or define you, just as Laura's love changed and revealed your potentials years ago. Or to passively let yourself be defined by your role as a father. Better to do the heavy lifting yourself. Get a counselor/coach or books to help guide you. But don't be defined by another woman or your children. This task is between you and God.
But for now, tears are your friends, your best medicine, and your lifeline to sanity--though there will be times when you'll think, "If I don't stop crying I'll go insane." It's okay. Deep inside, slow healing has already begun. Join your friends and volnation acquaintances in asking God to bless you, Dennis. I promise, He wants to.