Diagnosed with herpes but in a monogamous relationship

I was devastated when I was recently diagnosed with herpes. It looked and felt really sus that’s why I had the consultation. Although I just had it online due to COVID cases here.

I and my boyfriend have been together for about 5 years and we were each other’s firsts. When it comes to hygiene, I’m the most careful as I had histories of UTI when I was young. We are each other’s best friend and constantly together so that’s why we are just wondering how I got it out of the blue. Both of us never had cold sores as far as we were together.

Hope my medications will work as soon as possible. Any advice is really much appreciated. I’m new to this and had not asked my doctor properly during consultation as I was emotionally overwhelmed. But will have a follow-up check soon.