I really don’t know what to say here. You could have had this for a long time and recently infected her or it could be new for you both. There is simply no way to know.
‘But if your other partners tested negative for HSV 1 (even though the test is imperfect), it seems very unlikely to me that this infection in your wife is from this other partner since you and your wife didn’t have the kind of contact necessary for her to get it before she test. Is it a big problem with your wife that she thinks this came from the other partner? It might be helpful for your wife if the other partner tested negative by western blot.
I have to say that the likelihood of both of you having the exact same index value of 33 (it is not a percent) is like one in a million. So weird.