Did I make the right decision?

So I have a 1 month old. My first baby. I am getting cash assistance right now and they require father's info to continue payments. I need the money to care for my baby at the moment. The dad and I were seeing each other when him and his wife were getting divorced. Then he broke it off because he wanted to work things out with her to get his 2 year old back. I found out later that I was pregnant and told him. Haven't heard anything from him the whole time but now he is going to get a letter from child support services. Did I do the right thing? And should I let him know before he gets the letter?