Is he using me?

So I’m from South Africa and I go back home in August. I’ve been seeing this guy and we hangout atleast 3 times a week. We decided from the beginning that it would be better that it just be a casual thing since I’m going back to my country. Since that decision was made, a lot of feelings have developed and we told each other the other night that we’re falling in love with each other. He was also my first.. we have sex all the time and we have a really great connection, he treats me really well but what makes it difficult is that he treats my like a girlfriend all while he is also going on serious dates with this other girl ( they have not slept together) I know this is what we agreed to but is it normal for me to be completely heartbroken everytime I think about this. And I don’t believe this at all but sometimes I think maybe he is using me for sex. I’ve never been in a relationship before so this is just really difficult on me and I don’t really know how to go about the situation.