Age Gap

I'm 28, my SO is 49. I have never been so in love. What I have with him is what I've always wanted, and I know this is the man I am meant to be with. I can't be the only one in a relationship with this sort of age difference. My dilemma is telling my parents. I have a wonderful relationship with them, but I know the age thing is going to freak them out big time. They're going to worry and have the typical parental concerns. I will definitely tell them before he meets them, but I want the initial introductions to go smoothly and not be tense...what's the best way to allay any concerns or to convince them to treat him the same as any other guy I've brought home?