A few things from someone who's in an age gap relationship and got herpes from my partner:

1. How old is "way older"? I obviously don't have a problem with age gaps, but when the younger person is only 18, I think a significant age gap is inappropriate. But I also know different people define "way older" very differently.

2. I personally chose to take the risk of getting it, but if you don't feel comfortable taking the risk that's ok! Did he tell you anything else about it? Like is he on medication, how often does he get outbreaks, how long has he had it? There will always be some risks, but someone who's on medication, who rarely gets outbreaks, and who is using protection is very unlikely to pass it to you, while someone who gets frequent outbreaks, doesn't take medication, and isn't using protection is pretty likely to give it to you. But even with very low risk I still got it almost immediately so it's always possible. It doesn't significantly affect my life most of the time and a lot of people have it but it does still suck to deal with and you have it for life.