E.B.
My former sister-in-law (divorced now from my brother) had a very similar situation. She got pregnant after the most brief encounter (almost a one-night stand) and soon afterwards, while she was pregnant, she met my brother and they got married just before her baby turned one year old. Aside from informing the bio-dad about the birth, there was almost no contact, at my brother's insistence.
They did not tell her son that my brother was not his biological father, and did not tell him that he was nearly one year old at the time of their wedding, and was included in the ceremony (my brother promising to raise him like his own, etc). He grew up never imagining that the man he called Daddy was not, in fact, his biological father and that somewhere out there was the man who was biologically his father.
My ex-SIL knew who the father was, and like in your situation, the father was and is a good man, law-abiding, with a good career, and a solid husband and father to the family he eventually went on to have. He asked occasionally if he could meet his son, but my brother adamantly and angrily refused. My brother went on to insist that the boy never would be told that he was born out of wedlock to his mother by a completely different man whom he did not know existed.
It turned out to be a disaster. My brother's stubbornness, and my ex SIL's reluctant agreement to go along with her new husband's wishes, led to a terribly painful event when the boy was about 13 years old. Someone (a cousin), at a large family gathering, happened to mention my brother and his wife's wedding, and said to the boy "you were so cute in your little baby tux at the wedding". Gasps and awkward silence all around, as the boy looked from relative to relative, as it dawned upon everyone that the proverbial cat was out of the bag, in such a public way. Up to this point they had hidden most of their wedding photos except for ones that only included the bride and groom, not the wedding party, as the little boy was an unofficial ringbearer and bridesmaids and groomsmen were holding him in lots of photos.
So the boy learned, at age 13, that his daddy was not his biological father, and that the man who was his bio dad had been asking to meet him - not to have custody, not to start anything unpleasant, but simply to know him and send him a birthday gift or maybe have a visit. He had been very clear that he had no unpleasant or evil intentions and wanted my brother and ex-SIL to meet his wife and children. They lived quite far away and he made it clear that they would not intrude, but simply learn how his son was growing up. The boy cried for hours, saying that everything he ever knew had been a lie.
Now, my nephew (he's an adult) does not speak to my brother. My brother and ex-SIL got divorced. My nephew went to meet his bio dad but because there had been so much secrecy and deceit in his family, he was distrustful and suspicious. He still has a lot of trouble with trust and confidence. He doesn't attend family get-togethers, as it's first and foremost in his mind that all these aunts and uncles and cousins and grandparents all knew something important about him and no one had the courage to tell him and trust him with the truth. We begged my brother to celebrate the boy's life in some unique way, like calling their wedding anniversary a "we became a family day" or something, but he insisted on complete separation from the bio-dad and complete silence about the boy's birth.
If my ex-SIL had been honest with her son from the beginning, and if she had allowed him to meet the very nice man who was his bio-dad, and if my brother had not been so selfish and controlling and fearful, maybe things would be different today.
I know you want to respect your husband's wishes, but his wishes are not in the interest of truth. Being honest with your daughter, and trusting her with the truth about her bio-dad, affects much more than the bio-dad. It can affect her entire rest of her life and her ability to believe what you say and know who she is. It doesn't make your husband less of a daddy. It makes him more of a daddy, because he respects the truth and is grateful to the bio-dad for helping to create this lovely little girl.
All in all, this is more about your daughter's well-being than about your husband's fears or anger. Get a counselor's help in navigating this challenge.