Life is full of unexpected events. But you never, ever, stop to consider the basic fact that when you marry someone, you are literally marrying his entire family... The story below is an account of a frustrated daughter-in-law. The original poster (OP) had just welcomed a darling newborn boy with her now-husband. The baby is the husband's firstborn and OP's third child overall. At first, everything was going great for OP, but after the baby was delivered, her mother-in-law became involved and m…