I'm writing from a different perspective - a daughter who lost her Daddy way too early (and I was 30 when he passed away almost 2 years ago)! From day 1, Dad's attitude was "it is what it is" and really focused his time and energy in making sure that we spent quality HAPPY times together, and he couldn't stand it when we sat there and concerned ourselves with the later-ons, and the anger and the sadness. We actually got into a few arguements because I kept telling him it WASN'T okay and it really bothered me that he accepted it so easily. Thing is, I'm sure he really didn't accept it as easily as he let on. I had just had my first child when he was diagnosed, and I know it broke his heart to think of everything he would miss with his kids and grandkids when he was gone. He chose to help us deal with our grief in that year and a half from diagnosis to when he passed by letting us know that HE was going to be okay, and that he needed to know WE were going to be okay.
Once I figured that out, my attitude really did change. I decided it wasn't fair to him to make him feel somehow guilty by always being so upset that he would be leaving us, because clearly it wasn't his choice and was hurting him as much (or more) then it was hurting us, whether he let on that it was or not. Once I got that through my head, it was easier to face, and we often even joked about it (believe it or not)! He went to have a family ring made for my Mom out of his wedding band, and when the women asked when he needed it by, he said "well, soon... I don't know how much time I have left", and I burst into tears. When we walked outside he burst our laughing and said that the tears were perfect, and that we may as well use the "dying" card while we could. I remember starting to laugh and not being able to stop. He had that ring in hand 5 days later... ha ha.
Anyway, long post that could have been much shorter, I think it's just so important for us to realize that our loved ones need to know that we are going to be okay. It's okay to cry, and be mad and be sad, but I think we (or I, at least) needed to focus on helping THEM feel better... they are the ones that are going to have to leave, after all.
Now, 2 years later I am going to be having my second child (due just 3 days before the anniversary of his death), and as sad as I am, I really do know he's okay because he made sure I knew he would be. You have a beautiful family (I'm obsessed with your blog and instagram, by the way), and you will be fine afterwords. It won't always be easy, but like others have said, things have a way of working themselves out. For now, just continue to spend time with him and your kids. Make memories and know that it's true what they say... the memories will get you through. Oh, and one thing I wish I had was something from him with his voice. Sometimes there's nothing in the world I want more then to hear his voice. Just a thought for your kids. There are recordable books, and as cheesy as it sounds, I wish I had him read one for each of us while he was still healthy enough. It's a small keepsake that would have meant the world.
Thinking of you and your family.