I became facebook friends w/ an old high school lover. He invited me to dinner just to catch up. Should I go?

I befriended an old lover from high school on facebook just out of curiosity. He accepted and sent me a message telling me how great I looked and how he was happy to see me on facebook. I sent him a friendly but lukewarm response saying thanks. He sent me another message saying, "I don't know where you live but I'd definitely be interested in taking you to dinner some times. Just to catch up. I'll understand if you can't (-:" I thought sure, what's the harm and replied that we could have dinner as long as my boyfriend was okay with it. I jokingly mentioned it to my boyfriend who said that he thinks this guy just wants to recapture old times. . .have a few drinks, share memories, and have sex. He also said he doesn't understand why this guy would think that we needed to catch up given that we had a strictly sexual relationship. I was young (dumb, too) and he was an upperclassmen who invited me to skip class with him. We'd go to his house or for a drive and I gave him oral sex--which was never reciprocated. Then he seemed afraid of having sexual intercourse and a virgin I believe. Yeah, it seems like I got used and maybe I did but I was a willing participant and he was always a nice guy when we were together but we acted as if we didn't know each other during school. We saw each other some years later at a local college where he warmly greeted and embraced me openly in public and we exchanged numbers. We lost contact because I had a boyfriend and felt uncomfortable with his conversation which focused on how sexy he thought my body (legs, butt, thighs, etc) was especially in tight, short dresses or skirts. I love my boyfriend and want to respect him. Yet, I have thought about this invitation and have not decided to take up on it or to refuse. What should I do? A part of me wants to go just to show him what a great woman he missed out on and to show him that I've still got it, I am in great shape, happy, & in love! Especially since he is single but dating this less than attractive woman, overweight, and out of shape. Petty? Maybe but I am just being honest. Please, help!