If he already left you, the answer is no.
Leave him he must not love you as much as you love him or you can be sneaky and see what he does with her
First, if he's you're boyfriend, he doesn't, just as you don't really love him. See link below for why.
he will treat you like he really likes you like hugs you and tells you that he loves you and your the best he ever had
You should try asking him.
talk to the girl first and see if she really loves him, but if he doesn't feel the same way about her then don't end it.
If he really loves you, he will act like it and you won't have to ask. If you need proof, there's already something wrong.
well check and see who you really like more and who you think about most. Which one loves you more and treats you with respect.
Ask him to kiss you. If he kisses you on forehead or chiks first then definitely he loves you.
Hun, he has to really mean it & if he doesn't then he really doesn't love you. He must refer to, that he just really LIKES you a lot.
Ask her
If your boyfriend blocks you on Facebook, he may not want you to see what he's posting. Maybe he doesn't want to share everything with you but he can still love you.
You would really have to speak to her as she is the only one that would know the answer to this .