My ex remarried a few years ago to a woman who is 15 years younger than me, has a Ph.D., and is quite wealthy. I basically owe her my life. My boyfriend got arrested, I got pregnant, and our house almost burned down. She provided my children and me an apartment that she owns, paid for a nanny, and helped with getting the house rebuilt. My kids are over at their dad’s most afternoons (including my now 3-year-old, saving me day care fees). I am back on my feet and biting back nasty comments
whenever my kids talk about her.
biting back nasty commentsはどのような意味でしょうか？よろしくお願いします