Jack: Denial will always rear it's UGLY head, but if you can transfer all the GREAT times you shared together, the ugliness will go away!
He's in a better place now and you have to come to grips with that. When down, think of all the GREAT times you shared and let that be the focus!
It's hard! But when you think of anything, make it special times and you will sit there smiling! Your Dad is smiling back! He wants you to be happy!
I know it's tough, but when you replace the "what if's" with the precious time he spent with you and your family, and knowing he wants only the best for you, you can't help but to shed a small smile.
Sorry for rambling on!