He knew that love potion wouldn't make her his. That's why he didn't do it. , "this won't create real love." To top it off, he probably knew that he would never leave it at checking up on her. He obvoiusly missed her greatly and regretted that decision. However, I will also say that he is problematic because he seemed to hate everybody. It wasn't just Harry. His disdain for his students is well played out in the books. There's a valid reason why Harry suspected Snape of trying to get that stone but it wasn't covered in the movies.

During the time period that this was created for these would have been normal. Then there is the fact that this is pretty close to reality. No not all men are like Gaston. Education, such as in this time period, was not going to be very widespread (I bet the baker couldn't read either) so a woman being thus educated is odd. I give her kudos for not caring for sppearing different. Although she does care and her father saw more in her than would have been seen. I could go on and say that this is a fantasy story and a magic spell allows for playing room. Every good writer wants a sense of realism in their story and every good writer likes to have playing room. The old Disney movies cover this pretty well. The Lion King and Beauty and the Beast are srill some of the best they ever did. Aladdin was awesome as well.