Sex partner has two clusters of little bumps under tip of penis. they're flat and not red. he said they've always been there. don't trust him. herpes?

Probably warts: It seems more likely that these could be genital warts. Herpes lesions would be red and 'blister like' - and also are very painful. Warts would be 'fleshy' but could appear flat. Warts typically come in clusters as well. If you have an instinct not to trust someone, I would actually LISTEN to that. Your inner voice may know something that your conscious mind hasn't yet discovered.

Not herpes: Your description doesn't sound like herpes or any other STD, and no STD would last so long. Herpes lesions are blisters or open sores that never last more than 1-2 weeks. This is some sort of minor anatomical variant, probably normal periurethral glands, or maybe fordyce spots (prominent sebaceous glands) or pearly penile papules. These are normal in many men. Don't worry about this.