If I'm right in guessing what happened with your now ex husband, then I fully understand your not wanting to talk about it.
I also want you to know that it is 100% normal to be feeling these attachment issues, even if you had not gone through with the previous issues.
It is perfectly normal to feel sad and miss the one you care about.
Might I suggest two things.
Firstly, when you two are apart, instead of dwelling on his absence, think of all the great times you two have had together, embrace his absence by knowing that your day will get even better because you will soon be together again.
Secondly, and this one greatly depends on the type of person he is, and also how strong you two are connected.
Talk to him.
You may not feel comfortable revealing every single detail, atleast not right away. That's ok, theres always time for that later if need be.
Just let him in, let him know what you are feeling, and especially why you are feeling this way. Once he begins to understand what is going on, I am sure he would be more than happy to throw you a text here and there, a quick call on his lunch break etc.
Bringing him in will allow the two of you to work on this together, and should bring a happier outcome for both.
All the best, and good luck.