My SO lied to me and it's driving me nuts.

M/34 married for 9 years, 2 children, pretty solid marriage, no major setbacks the usual marital quarrels every once in a while, nothing major.

So I found out today (with evidence) that my wife explicitly lied to me and then backed up that lie (or atleast attempted to). When I confronted her about it, showed her the evidence, she made up a story implicating one of her coworkers and even offered to have me talk to her to prove she was telling the truth. When I said fine call her ill talk to her she gaslighted me and called me things she shouldn't have.

What did she lie about? It's beside the point. It was a trivial thing , the problem is her feeling the need to lie and then concoct stories about that lie once confronted instead of coming clean.

She has, at the time of me writing this, gone to her parents house with the kids saying she needs to get away from me. Another unwarranted over reaction in my opinion.

I know she will be back obviously. Probably even tonight. What's driving me nuts is that in almost 10 years of marriage, she has done nothing of the sort, nor have I given her reason to. I don't doubt she's cheating for one second, but her treatment of this situation is making me more and more skeptical that there's something else going on.

Am I wrong?

Edit:

Since the majority of you are demanding context:

She has been having fever on and off for a few days. I've been taking care of her (as I should be, no point scoring here). Today she asked me to drop the kids to school on my way to work (something she usually does) which I readily agreed to as I wanted her to rest. After dropping thr kidd I decided to call jn late at work and spend a few hours with her at home so she would be pleased and in case she needed anything. When j got home, to my surprise she was out of bed, had makeup in and dressed formally. On enquiring she said her boss at work had called and she needed to ho immediately even though she had taken thr day off already by calling in sick. I opined that she shouldn't let her boss drag her into work when she was obviously unwell. She said she couldn't argue rn . She left. An hour later I got an email that my card (the one my wife has) was used at English tea house, an upscale eatery here in Gulberg , Lahore . I sent her the email receipt along with a query and she replied she had given thr card to her coworker as ETC had a 50% discount on my banks card and that her coworker would pay her back. I called her and she declined the call . An hour later she called me and said she could put her coworker on thr phone if I didn't belive her.

So...who's in the wrong?

Update (12 hours later)

Update: (To answer a lot of your queries) I still haven't had the chance to sit down and have a mature discussion with her yet. No, I don't think she's cheating on me. The thought crossed my mind to go to ETH and check CCTV footage at the time of the transaction as some of you suggested (even though it will be a hassle without a warrant or strong connections) but its pointless. I know she was there. She knows I know she was there. I also know she was probably there with coworkers/friends and not on like a date. Which is why it's infuriating that she had to lie. Was she embarrassed that she was sick and I was taking care of her and that I'd be mad if she told me she had a breakfast meetup with friends? I would probably have advised her to rest yes but I would never have forced her not to go...why lie then? And why evade after I confronted her?