How successful is this app?

So my boyfriend never wanted kids ever. When him and I got together my daughter was just over 5 months old (her sperm donor isn't in the picture at all) and my boyfriend took her in as his own and she calls him daddy :) but my boyfriend actually wants to have a baby now and we've been trying. I'm not concerned about my kids being close in age, I actually prefer that they will be. How many of you have used this app with success?