Angelic- this regularly happens, a dog just gets 'fed up' with all the warnings and begins to give warnings. My guy's family has a Miniature Schnauzer and he gives warning bites and growls and 'attacks' when rough played with and most of the time he isn't being aggressive or trying to hurt, he is being played with rough and is 'playing' back.
Im glad you will rehome him to a good home. Bostons are good with kids because of their mellow personalities, but aren't because they're fragile, delicate dogs. If your kids like to rough play, you need a hardier, perhaps larger, breed of dog. A Boston just isn't that, unfortunately. I hope you find a breed that does better! :)
Shimi- that's terrible!! I hope she recovers nicely. ;(
Ladies, this is why regular gyro/OBGYN visits are not something to avoid!!