You are doing the perfect thing bringing up memories. Make sure his pictures never go away. Talking about him keeps his memory alive for them as hard as it is for you.
Corey.....Just today I was listening to saved voice messages from my husband because I need to hear his voice every now and then. Calling your husband's phone to hear his message is normal.
You're doing the right things by talking about your husband to your kids. That in itself keeps his memory alive. With kids you never really know what kind of influence you have on them until you hear them say something out of the blue and realize they have been paying attention. I'm sure they miss their father very much. It's possible they don't want to make you sad and therefore don't bring him up first. My husband was 3 years old when he lost his mother and he missed her for his entire life. There's no way you're kids don't miss their father, they're just too young to put words to it the way we do.
Corey; our kids were in their 20's when my wife / their mother died... I have no fear they will forget her; I regularly talk about her, and whenever they uncover a photo they post it on FB.
I happened upon voicemails of hers when I finally got to closing accounts; I was elated, and saved them, and did backups, and backups, and backups. We made lots of VCRs of the kids when they were young, but none of each other. I beat myself up over that, I'll tell you.
It's been 3 years since she died, and never a day goes by without a tear; at least now I rarely choke up in public when something twigs a memory: sound, smell, deja-vu... I talk to her every day, throughout the day -- just the two of us.
As you know, there are many angels on this site, and it is the perfect place to vent on those really crappy days. I'm having fewer crappy days, and I'm sure you will, too. We are all on this bereavement path, but the twists and turns are different for each of us.
Corey ... I am so very sorry you are fearful of your children forgetting their father, but believe me they have not. Adults grieve a little different than children. I believe in a family that each person in that family is trying to be strong for each other and walking on egg shells. May I suggest just one time in the evening when your household has calmed down for the evening to sit down with your children and just talk about your husband and let them discuss how they feel. Let them know it's OK to cry and that all of you are strong and should lean on each other. This was none of you are walking on egg shells around each other.
It wonderful you keep bringing your husband up and keep pictures around and going through old albums every so often or just bringing up a fun memory that included all of you is a healing process. The others here with children (I do not have children) say it the best so be assured your children will never forget their father.