My (40M) wife (39F) purposefully excluded a coworker (32F) from my birthday party and then lied about it. I'm having trouble facing both of them.

Last week my wife threw me a big surprise birthday for my 40th birthday. She invited all my closest friends, family members, and coworkers. I work in a small office of 6 people, and 5 out of the 6 were there, so in my mind I assumed she invited all 6. I noticed one coworker wasn't there and I casually asked another coworker where she was. This coworker said, "Yeah, she couldn't make it!" and that was it. We moved on.

The next Monday at work, I saw this coworker (32F) and we started with our usual morning small talk which includes a weekend recap. She asked me how my party was. I said, "It was great, sucks you couldn't make it!". This coworker just looked at me very flatly and said, "I uh, wasn't invited". I paused, and apologized and I felt mortified. I'm assuming she knew because she had seem the pictures on Facebook, but she said she had heard people around the office talking about it and she just never got invited.

I was not only extremely embarrassed for her, but I also took it very personally. I went right to my wife later that day and asked why she excluded this coworker. She then went to "No, she was invited, she was busy blah blah". I said I had just talked to Coworker who confirmed she wasn't invited. My wife then said, "I couldn't do it. She's younger than all of us, I've seen you looking at her. I've seen how she looks at you". I then just asked if my wife didn't invite her because she thinks I'm attracted to her and all she said was, "I didn't say that". I asked why she also had another coworker cover for her and say she couldn't make it and she asked why I was so concerned that she wasn't there. I told her how shitty it was to do that because of her own insecurity and we just haven't talked about it since. I genuinely do not have anything for this coworker, so my wife has nothing to worry about. I don't think anything we have done has ever given her that impression and all she could say was how we look at each other. There's so much nothing going on I don't even have the motivation to prove it to her because I know she won't believe it.

It's been a few days an I feel kind of disgusted and embarrassed when I look at my wife. When I see this coworker, I feel mortified, I can only imagine what it must have been like for her, but I'm also conflicted because I don't want to seem I care about her only because I found out she wasn't invited. I'm struggling most with my wife because I feel what she did was immature and petty and she's never treated anyone like this before. My wife hasn't brought it up, and it's affecting my productivity at work. It's only been a few days but I'm having trouble seeing my wife as anything but a mean girl not inviting everyone but the weird kid to her birthday party at school.