I’m so sorry this is happening to you.
Are you absolutely certain that these are all herpes outbreaks? Have you had any of them swab tested at all?
The next thing you could try is switching to Famvir. The suppression dose is 250 mg twice a day. For some people this works better than Valtrex. How long are your outbreaks lasting? What is the presentation like? Are you on any hormone therapy, like birth control pills?