Unfortunately, most men do not find out that a woman has transformed from a gentle lamb to a tigress except until it is too late (after marriage).
Remember, women are experts when it comes to putting on a pleasant front to get what they want. They want a ring, they will do whatever it takes until you give them what they want.
Also, many women let their bodies go after marriage. They don't exercise, watch what they eat or put in effort to look good. Why? She has the monopoly of you in a monogamy, that's why. She got you by the balls, what can you do?
So, don't marry at all.