Why do serial cheaters still want to stay married?

I’ve been contemplating using monitoring apps to protect myself, but I wonder if it’s crossing a moral line. Have others here used tools like these? Do they help or cause more harm in the long run? I worry about privacy invasion, but also about trust issues. Would love to hear from those who’ve been in similar situations—did monitoring work for you or make things worse? Is it worth it if it feels like a betrayal? Just trying to understand if it’s an acceptable way to look out for myself or if it’s morally questionable. Thanks in advance for sharing your thoughts and experiences.