If he has been a good father figure for most of their life, then he's still their "dad." And you're not a bad mom for not being with the biological father if you have someone who makes your family whole. Perhaps you could start with how babies are made, and let them know that someone else helped you make them, but now their "dad" is helping you take care of them and do all the things their biological dad isn't around to do. That doesn't change the definition of a dad. If you have a close girl-friend you consider like a sister maybe you could use that to explain, that even though you aren't biologically sisters, you still do things for each other that sisters do and that's what's important--not genetics. Be open to their questions and sensitive to how they are feeling, and don't let your emotions toward either "dad" cloud your perception of how this news makes them feel. Good luck!
at 5:09 PM on Jun. 21, 2008