Dear Lennie: I've been dating this guy for three weeks. We tried to have sex for the first time last night, and I'm not interested in trying again. I saw meds in his bathroom—happy pills that make dicks limp. And I didn't like the smell of his linen or of him. So how do I say no thanks? I don't want to hurt him, but it's not working. I'm done.
Honestly, this may sound harsh, but if the shoe were on the other foot, do you really think he'd care about hurting your feelings? It's only three weeks, you're not exclusive, you just had sex for the first time (bravo for waiting, btw). If there is no chemistry, you don't owe him an explanation, and you don't need to let him down easy. Just tell him you're not feeling it. If he ask for clarification, just say "not feeling it, is not feeling it. There's nothing more to say". You don't need to get into a whole drama about seeing the meds, or not liking his body odor, or any of that. That will become hurtful and a big heated conversation. If you're afraid of confrontation, you could do it in an email or text, but that's really taking the easy way out. Just pick up the phone and say "it's not working".