Help!!

Sarah • I'm a proud mommy of a beautiful little girl. I'm also madly in love with my wonderful soon to be husband.

So I just found out that my daughter’s biological father just had another baby should I try explaining it my daughter which is two and half or not even tell her. She hasn’t seen her biological father since July of last year and she more into my fiancé then her father. What should I do?? This would make her biological father have three daughter. He hasn’t seen his first daughter since she was 2 years old.