She could’ve been infected orally and genitally at the same time . Has she had a obvious cold sore ever ? Or she could’ve been infected genitally from receiving oral sex and is just now having an outbreak . Some people have outbreaks days , weeks , months and years after getting infected . Genital hsv1 is quit benign and it’s rarely transmitted do to few recurrences and low shedding rate which = low transmission . Did she get her outbreak swabbed ? If not she needs to do so she can know her hsv1 infection is in fact genital .
Totally agree with Justawoman - if this was just a blood test, that doesn't mean that she has ghsv1.
Herpes doesn't "migrate" to other areas of the body. If she had a sore cultured, and it came back as hsv1, that means she got it from oral sex. (Oral hsv1 can sometimes migrate to the eye, but herpes will never migrate from the mouth to the genitals. Herpes infects nerve groups. Genital herpes infects the sacral ganglia, which affects the boxer shorts area. Oral herpes affects the trigeminal nerve, which only affect the face.)
When she got it is impossible to know. The IgG herpes type 1 blood test misses 30% of infections, so you could indeed have it and transmitted it to your wife if you perform oral on her. She could have had it for years - prior to knowing you- and for some reason is just now getting an outbreak.
If she had an IgG blood test done, and it was positive, all it means is that she's had the infection for longer than a few weeks. It can take up to 4 months to develop antibodies, but many develop them much sooner.
This may be something you never really figure out. If you're concerned that she was unfaithful, this isn't nearly enough evidence alone to determine that.