How wonderful for you to have had such a wonderful man for so many years!!! He sounds like he was a tremendous blessing to you and such people are never lost as long as someone remains who loved them and who was effected by their love.
Before my Father passed away, he told me something that has sustained me and kept me going. He said "As long as you don't forget me, I will ALWAYS be with you". He is with me everyday. I hurt with you for your loss of a Father, hero and friend. When you see something that reminds you of him, it could be your Father showing it to you. Acknowege him and enjoy the memories. The pain NEVER goes away but it will lessen in time.