I am honestly suprised at some of the responses on here.
Years ago, when I met my 2nd husband, the only timescale that was appropriate for introducing children to new partners was one that you set for yourself, not by other people who don't even know you, your children, or your circumstances.
Surely we are capable of making that decision, and knowing ourselves, when it feels right depending on the man involved, and the child with whom they are to be introduced to.
For some reason MN thinks that anyone who introduces a new man to their child before 6 months is a terrible mother. What do they think is going to happen?
I met my DH and within a couple of months of meeting him knew that he was for keeps and I wanted to marry this man. He felt the same as I did. We met each others families and he met my DD from my first marriage.
The timing felt right to introduce them and they got on like a house on fire and he regularly started to stay overnight in our home, before moving in with us completely after 8 months together.
I never once saw this (or him) as any kind of risk because I trusted this man and it turns out I was right to.
We married, he adopted her, and he has been a loving Dad to her now for over 20 years (and counting)