People keep making fun of me because I'm in love with a man that is mentally delayed, they need to mind their business right?

Are these people single or maybe just unhappy in the relationships their in? Could just be jealousy. They see you happy and found the one thing they could make fun of you with. If you're happy then it doesn't matter what they think. If it bothers you alot you should say something and if they don't stop then maybe you shouldn't hang around them anymore.