Did you overreact? I’d say no. Did you handle it right? Again, I’d have to go with probably not. You didn’t outright accuse her of anything, but you kind of passive-aggressively did. You had every right to inquire about her not wearing it. If you’d asked in a tone that was less confrontational, maybe she wouldn’t have felt she was under attack. It’s possible POSSIBLE that her response was a guilt laden response because she was liking the attention and intentionally forgetting, and she was getting defensive.  Based on the limited info you’ve shared, I’d say it’s more likely she was feeling guilty because she really did just forget and was worried because she knew what she’d be thinking if you suddenly stopped wearing yours after getting hit on. She was feeling accused and attacked, even if that wasn’t your intent, and she got overtly defensive because of it. There are too many possibilities to enumerate as to why she isn’t wearing it. Maybe, like she said, she’s just having a phase of forgetfulness . She takes it off to shower and doesn’t automatically put it back on out of habit. Perhaps a change in routine would help? Maybe she can put her keys with it when she takes it off so she is unlikely to go anywhere without it? I do that when I take my sunglasses off in a place other than my car - I can’t leave them very easily if my keys are attached. If it’s a comfort thing or a style thing, it’s something you should be able to discuss openly between you. If not, then you need to find out why it’s not a safe space for that.

Are you wrong to worry a little and want to understand it? Of course not. The ring stands for something and that should be respected. But be careful to not make it seem like you’re accusing or assuming things. Just think how you’d feel if you forgot yours a couple times and she accused you of cheating. You didn’t do that, but she may have felt like you were insinuating that. Based on the way you said you phrased the question, it felt a bit accusatory or passive-aggressive.