Why didn't my boyfriend want me to say hi to his neighbor which is a girl and I happen to know her?

I find this very weird but I came from vacations I (27 y/o) was out of the country for like 2 months, so I came back and I went out with my boyfriend ( 36y/o) yesterday and before we were getting read for him to bring me back home , he told he did not want me to say hi to his front house neighbor which happens to be a girl and her family, and in fact I happen to know her from the gym that I used to go.

Anyways I asked him why? and he said because he had parked the car close to her house the other days and they were looking at him in a weird attitude manner, since he is a foreigner he has these ''ideas'', and when we were walking out of his house he told me to walk towards the front of the car and not behind the car (which was closer to her since she was outside chatting with some other girl).

tl;dr: I wonder if he has cheated with her, cause I find it so weird that he did not want me to say hi to her, he was like '' I don't want you to say hi to those people'' The real reason I don't know,,,, I mean they are poor and we live in the Caribbean but I still find it Awkward and weird, what do you Guys think? I would love to see her one day and ask her stuff, but I don't have her mobile, neither her Facebook, but I would love to.