What am I doing wrong?

Todd

So to start I already have a child from a previous relationship, but in my current relationship my wife, and I have been trying for about 6 months. The last time it took no time and my ex was pregnant, but she also held out on me a lot so I had a lot of buildup. My wife though is like me, she can't get enough. We went from sex everyday 4 times or more a day now down to once or twice on the second day. Still no baby. is it me or could it be her?