I have a friend who was in the same situation. It's sad but better for everyone involved. But if someone does ask, tell them. Once they start getting some age on them, years old, I'm open to that because if they haven't worked it out in five years, they're probably not going to. If you and he get married, then yes, you will officially be the stepmother.
Ask A Very Smart Brotha: Should I Date A Man With A Newborn Baby?
Give her time and give her space.
I'm dating someone with a newborn (7 days old).
Any woman with an ounce of self - love, respect and class wouldn't even go there. Keep it simple. Most of the time, relationships with kids involved end when the kids are older, not before they are born.