I'm not a mom OP but I lost two of my siblings when they were both really young. Even though my mom (father not in the picture) still goes through it, and they both died over 8 years ago, all I'll say is that it can get better with time.
It may be different bc you and your husband are going through this together, but one thing that I know made a difference was not keeping those emotions bottled up. When my mom wanted to cry she broke down and cried. When I felt upset I just had to ride with that. My family isn't very emotional so we tend to bottle things up, but a psychotherapist who used to give free sessions once a month at church advised that we talk it through. So every year, we mark the anniversary of their deaths, celebrate their birthdays, and do other things to commemorate their lives.
It helps me to think that theyre still here. Sometimes something random will happen and I just know that they were right there. Like my lil bro used to play mad jokes on my our mom...last week all the cans in her overhead kitchen cabinet fell out at the same time and one hit her on the head. He used to do that all the time and would whoop his lil tail. She called me up and told me, and we both shouted "Marvin!" at the same time and burst out laughing. Hopefully laughing about it will get easier but first you have to make yourself comfortable with talking about his life.