How would you handle this?please help!

Me and my soon to be husband met when I was 2 months pregnant from a relationship with a abusive man, Being the first time I got pregnant I didnt want to abort the baby, I told my boyfriend the whole story and he did not care the baby was not his, My daughter is now 1 year old and sees him as her Daddy, She even said PAPA first, I can see how attached she is to him, My Concern is how will I someday explain to my daughter that he Is NOT her biological dad. I am now 1 month pregnant and Im also so sad to think that someday when she knows the truth she will be hurt by knowing her brother/sister is my boyfriend "Biological" son/daughter and she is not. 😕😔