Brief Answer:
Likely you got from new partner

Detailed Answer:
Hi
Thank you for query. I am Dr Bharatesh D Basti dermatologist and venerologist answering.
it is not clear about the site whether it is genital or oral.
Hsv1 or 2 , whether oral or genital , can spread even by touch or kiss. So it need not be only Std as a way to transmit.
herpes can be transmitted more during the active infection is present.
If your ex-partner did not have it, it is likely that you have acquired from the new partner.
Herpes is known for its recurrence and the severity goes on reducing with the subsequent appearance over years.
it is best to avoid contact with each other when the lesions are active whether genital or oral.
You can take antiviral treatment when active lesion present and if need be take suppressive therapy antiviral like acyclovir weekly 400 mg once for 6 - 12 months to prevent recurrence.
If you need any clarification you can get back to me.
Thank you
Dr Bharatesh

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