Feeling ignored

I was surfing the web today looking for some answers and I found your website, and it immediately looked helpful. My husband has ADHD, I don't. We met in Italy where he was stationed for the military, got married and I followed him here to the States. Our relationship has been pretty good...we have a 1 year old boy and a baby girl on the way. When my son was 10 months old, I was diagnosed with Post Partum Depression. In the months prior to this "discovery", I believe our relationship sunk. The communication stopped and he went looking for attention talking to random people online. He did everything behind my back, and I just recently found out that he was having cyber sex and God knows what else while online. I got really hurt and asked me not to lie anymore, but to come clean about everything so I could process the whole thing and start over. He told me everything was out, but I found out more. Useless to say how I feel, but I am trying to understand what caused him to have this immature behaviour. Last Sunday he left for Texas, where he will be "deployed" for 4 months. It has only been a week, but it has been a really painful one. I feel really ignored and neglected. If I ask him to please pay more attention to me and his son, he told me I am needy or he starts yelling and never apologizes. I am always the one that has to call or text him and it is getting old. I don't know how to deal with this on my own. I feel like I am going to explode. I am now thinking about totally ignore him for a while and see what his reaction could be.