Boys are dumb

So I’ve been dating this guy for 2 years but we’ve been close friends for about 5 years now. he’s a good guy & we’ve been through a lot. He went on vacation this summer and he went on & on & on about how he misses me & loves me & he apologize for not being the good boyfriend that I had once knew. He apologized out of no where & when he got back from his trip.. we were so happy to see each other & the same night we slept together then he left after and wanted the day to himself the next day.. why is that?