Honesty Is the Best Policy
It sounds like this person should spend less time on Reddit and more time communicating with his wife. Keeping something so big from her can lead to problems down the road. If he isn’t ready to have kids and wants to spend some time focusing on their marriage and their jobs, that’s perfectly fine.
I’m sure that if he explained the situation calmly and reasonably, his wife would understand. Even if she doesn’t, manipulating her cycle and keeping this secret from her is definitely not going to solve the issue. If they want different things and they can’t come to an understanding, maybe they don’t belong together.