I recently gave birth and found out today that my husband has been chatting online with all of his exes these last few weeks. (he hasn't been intouch with them for years). He also failed to mention to them that he is a new dad. When I asked him why, he says he doesn't want to hurt them. Am I unreasonable to feel upset about his behaviour?

Just to share my personal experience, my ex husband was exactly like yours and said the exact same thing. What happened? He ended up having an affair with one of them and I filed for a divorce 3 weeks after I gave birth. Have a good talk with him and tell him why it concerns you very much. Otherwise, it's not healthy for your child to grow up in such an environment where his/her father thinks its perfectly okay to hide his real identity from other women.