Boyfriend ignoring me

Br

So on Thursday my uncle asked me to go to the movies with him, his treat. He’s my mothers younger brother so we’re kinda close in age where we can hang out (I’m 23 he’s 28). I was getting ready and my bf called and I told him I was going with my uncle. His response: “you never told me you have an uncle.” Anyway long story short, he’s been ignoring me ever since and it’s starting to piss me off. This is the second time he pulled this stunt. Last time my aunt was in town and when I took her out he sent me all kinds of accusatory messages. I hate feeling like I’ve done something wrong when I haven’t. Advice?