@alexavier,
You consider this a misunderstanding, right?
Have you considered that, while you should be proud of your children, that your partner dearly wants to be able to be proud of his children? Have you considered that many men in his profession would feel shamed to have a son in prison? Have you also considered the anxiety he would feel if other prisoners found out that his son's father was a prison guard? ...have you considered how powerless he would feel to remedy this situation (because he is in fact powerless to fix it)?....and have you considered how talking about your good children in front of him would cause him a great deal of pain etc?
Now...all that doesn't mean that you shouldn't be able to express pride in your children -
you should be able to do so. What it means is that the two of you need to come to an understanding of where you are each at, and what you need from each other, so that you can both get what you need, and express what you desire to...without deep hurt being created.
In other words, it's time the two of you sat down and spilled your guts on what each of you are truly feeling...because as partners, you are both in this together, right? And so you are there to support each other, as well as lift each other up to a brighter degree of life, right?
This isn't a conversation that can be avoided without long term consequences.
Counsellors can work too, if you are unable to have this sort of conversation successfully without one.