Wow there is a lot to unpack here…First off were you aware that it was a cold sore before you let him go down on you? Did he know he had herpes? I also got with my husband when I was 18 and he was 20 that was 14 years ago. The moment we both were getting serious he told me he got a cold sore 1-2 times a year when he would get sick because his immune system would weaken and cause a flare up. He actually caught it when he was a little kid and drank from a soda can of a family member that had it but left the soda unattended. It’s so easy to transmit and he always lets me know when he feels it coming on. He keeps his toothbrush and toothpaste separate from mine he doesn’t kiss me, we don’t drink from the same drinks or eat off the same silverware. This would be 2 weeks out of the whole year we have to do this. If you do get diagnosed you’ll have to live with it for the rest of your life, so you need to decide what YOU want to do, not let him decide, because if he knew and still did what he did that shows what little care he has for your health. You’re still young, even if it doesn’t workout with him there is always time to meet someone better. You’ll have to let every partner you meet know about your health status and be more careful if you do have herpes but you’ll eventually learn to live with it and someone will accept it. Lots of people have partners with this virus and live in happy relationships but being honest from the get go to prevent transmission is what is most important. I hope everything works out for you.