Why does my fiancé lie to his family about being on a date with me? He makes up lies that he’s doing something else without including me.?
Because he’s embarrassed of you, doesn’t want them to know about you and doesn’t want you involved with them. I’m sorry but that’s a fact. If he truly loved you and actually were your fiancé he would never lie about you and would absolutely have you around his family without question. He probably bought you a ring to placate you and keep you where he wants you. Engagements can easily be broken or faked, especially if his family don’t know about you.
Why are you calling this guy your fiance when it's clear he lies too easily? This will go on for ever, unless you put a stop to it. If I were you, I'd dump him.
If you two aren't both actively engaged in the hard work of preparing for your marriage (not the wedding, the MARRIAGE), hard work like learning how to be "one of the family" among your future in-laws, hard work like helping your future spouse become part of your own birth family, then you're not both serious about getting married. The proposal, the ring, the calling each other "fiancé" and "fiancée" are minor facets of engagement compared to the "hard work of preparing for the marriage." If he's just giving you the trimmings without throwing himself into preparing for married life, then he is just TALKING engagement and isn't seriously about making a strong and happy marriage with you.