My boyfriend thinks I cheated on him on a family vacation

So I went to Jamaica this past week with my parents and two brothers. My boyfriend was being weird while I was gone some of the time because I didn’t have cell service and couldn’t talk to him as much as he wanted. Well I come home to him and after we have sex a bunch of times he tells me that I must have cheated on him in Jamaica because my vagina feels different and “loose” to the point he actually said I must have had a black dick in me while I I was there. What kind of person says something like that? I DID NOT CHEAT ON HIM NOR WOULD I EVER. I didn’t even meet any guys there or let anything get to the point of me even having a private conversation with a guy. I’m sick to my stomach and haven’t stopped crying because he’s so hell bent that I cheated on him. I need help!!! I need advice. I’m going crazy over this. I just started my period today so I haven’t stopped crying about this and I feel lost. He’s never been crazy like this before I don’t know what’s going on or why he’s accusing me of this but all it’s doing is making me feel horrible about myself because I think I’m not good enough for him sexually anymore. Let me know what you ladies think.