Original answer
You are already infected. The HSV is indeed dormant in your body. It
keeps trying to get out, till your immune system is off guard and it
will present as a cold sore. So when you don't have a cold sore your
immune system is in control and you can't get "more infected" by your
wife. So you can kiss without worries.
The next question is, do you really want to if she has a sore ;)
Update:
I'm new here, i thought I keep it simple. I will try to provide some evidence and complete the answer:
HSV-1 infects mucosal cells, like the ones in mouth and genitalia. After infection the HSV virus infects innervating neurons causing a latent infection. While the mucosal cells are infected, CD8+ cells (which kill virus infected cells) "learn" to recognize the virus and kill it of. As long as your CD8+ cells function normally the virus cannot reactivate. Also antibodies agains the infecting virus are formed, protecting against reinfection (theoretically you could also reinfect yourself) (1)
As @YviDe pointed out it is possible to get infected with multiple strains. In this a small study with 13 HSV-1 infect persons 2 where infected with more than 1 strain (2) However, there is also evidence an infection with HSV can protect against an infection with another strain. (3)
Now, lets assume you and your wife have the same strain of virus. Then the likelihood of you reinfecting yourself is much higher than she infecting you, since you drink from your infected glass and use your infected toothbrush etc.
If she has a different strain things are uncertain. As pointed out, your current infection could protect you but depending on numerous factors you can get reinfected or not with the different strain. If you have a cold sore your immune system (partly) compromised, so at that moment your susceptibility for a infection by this different strain is probably higher.
However, changes that you get infected anyway while living under the same roof is pretty high.
If I where you, I would worry about it to much since you can't be sure about anything without genetic sequencing of your and your wifes HSV-1 virus.
(1) Egan KP et al, Immunological control of herpes simplex virus infections, 2013
(2) Roest RW et al, Genotypic analysis of sequential genital herpes simplex virus type 1 (HSV-1) isolates of patients with recurrent HSV-1 associated genital herpes, 2014
(3) Stanberry LR et al, Longitudinal risk of herpes simplex virus (HSV) type 1, HSV type 2, and cytomegalovirus infections among young adolescent girls, 2004