Prego, I am reading a book you should read: "surviving infidelity" by Rona Subotnik & Gloria Harris
Here is a passage I had to quote (page 36):
"It is not unusual for therapists to see cases of fathers having affairs at the time a child is born. This is hard for many people to understand. The birth of a child is a positive event, one that people believe should bring happiness, and so they are surprised to find it precipitates an estrangement. In reality, the unfaithful spouse is acting out on the anxiety that comes with new expectations and responsibility. This is a stressfull time, with many things happening.
[...] They are required to grow up. This can be frightening to someone who feels he is not up to the challenge. For some fathers the anxiety is so acute that they cope by having sex with someone else."
