How to know if guys are using you?

Jessica
So I have been seeing this guy for a little while and we arnt officially dating nothing is official I guess but we do see eachother and Hook up and I have been used before by my last boyfriend so I'm being very careful with what I do with this guy just so I don't make the same mistake again but things got a bit sus, he told me he loved me... But he only seems like he wants to talk to me when he's horny, other times he gets bored and stops Talking or will just ignore me, he always randomly grabs my ass and when I asked him why he said it was so everyone knew you were my girl but ... I'm not I guess, I just don't know if this is different or if I'm over thinking it