Do women ever take accountability?

Why is it so hard for women to just say “I’m sorry?

I recently found out my ex-girlfriend was cheating on me after I noticed some strange behavior. I ended up installing a spyware on her phone, and sure enough, it confirmed what I suspected. When I confronted her about it, she denied everything. But when I showed her the proof, instead of owning up to it, she flipped it back on me questioning why I tracked her in the first place, accusing me of not trusting her, and completely avoiding the issue at hand. It felt like pure gaslighting, and I’m still trying to wrap my head around why some people can’t just apologize when they’re in the wrong.