At the end of October I went through something very similar to this. Fifteen years ago I was with a man just once and got pregnant, I felt horrible because he was married. I kept my mouth shut and went on with my life and married a man that knew the truth but choose to raise my son as his own. At the end of October I came into contact with the man I had a one night stand with, he is now divorced and said that he saw me a few months after our night together and saw that I was pregnant and asked was my son his. I told him I wasn't 100% sure so we had a DNA test that said he wasn't my ex-husbands so I knew this man was the only other one I had been with. We told my son(who is 14) the truth the first of Nov., it broke my heart to hurt him, but I had kept it a secret long enough and like you thought he deserved to know his other family if he wanted to. Since then this man and I have been dating and we are just taking it very slow letting my son do this at his own pace. He loves his dad that raised him and at this point is not looking to have another father, but he is getting to know him and really likes him alot and likes having him around. I agree with the other statements with your daughter being older I think it is best to let her reach out, just be there for her no matter what the out come is because she will need you.