Does Depression Come Out as Anger

My ex was constantly angry, sometimes before anyone spoke to him! Being the person I am, I tried to understand, went to therapy myself, where I was told that the problem needed to come in. I battled that for nearly 10 years till I gave up, but would really like to have some answers to what baffled me for so long. Sometimes (not often) he would even apologize and say he did not know why he acted like that, but more times than not he was simply angry and if I didn’t know the reason, he certainly wasn’t going