What should you do if your boyfriend (the person you love) is going out with you and another girl?

If he's going out with somebody else as well he's not your boyfriend.

I would ask him what the **** is going on,then I'd probably dump him.

You love him, he's just playing the field.

You two are dating, you're not boyfriend and girlfriend. So you have to decide. Do you want a boyfriend, someone that's loyal to only you, or are you willing to casually date?

He's not ready to be in a relationship. You two aren't on the same page. It's time to start reading a new book.

Has there been some official 'im your girlfriend, you're my boyfriend' stuff?
If not then he may just see you as a friends with benefits
If he is actually your boyfriend then I don't know about you but I wouldn't really be putting up with that, its cheating and not worth the time or the tears.

If your in that casual friends with benefits stage and you want more you need to tell him straight out that its her or you, it sounds a little harsh I know but if he really likes you he'll do it.. if not, then chances are he's not really worth it

Good luck!

You may love him, but does HE know he is your boyfriend?

You need to open the lines of communication and make sure he is your boyfriend. You may love him but that doesn't qualify him as your boyfriend.