This is what I did when I was still dating - I pretended like nothing until the first inevitable block, then I just went "sorry, I have a stutter" then (tried to) continue where I left off. Then I silently gauged their reactions. Every time they either didn't notice or didn't care - which in turn made me stutter less. Once "the cat was out of the bag" I would pick a time to tell her about my condition and what she could do to help me. To me that was very important because for most people finishing my sentences IS helping (the thought is nice, so can't really fault them for that) - and I don't want to make a new potential girlfriend think she is helping me when she is in fact making it worse. Apart from that, it is the age-old "if your stutter is bothering him, then he isn't someone you're meant to spend time with either".