How to confront boyfriend about acting like he's single with other women?

brake up he clearly doesn't like you enough

Let him!

Follow suit

He gets upset

Let's make a deal ...

Could be lots of reasons.
Could be that he's an evil cheating bastard out for a bit on the side.
Could be that he thinks you're due to leave him any moment and doesn't want to totally burn all his bridges by solidly stitching himself to you.
Could be that he just plain feels weird been seen as part of a couple and not a normal guy. I'm a bit like that. I'm always "single" even when I have a girlfriend. Its not that I would cheat on her or try to. Its just...it feels weird and not like I'm me to be stamped as me and her, not just me.
Lots of reasons

"Why does he not tell her he is in a serious relationship?"

Because it makes him feel good. It's good for his ego to know that other women find him attractive.

How do you confront him? Just use words. And try not to be so judgemental. It's not like he cheated on you. He did have phone sex with these girls. He wasn't sexting them or swapping pics.

He just got complimented, and said thanks, and complimented them back.

No big deal.

give him the most amazing head ever..back to reality oo there goes gravity.. ;)

either tell him not to do it anymore

or

have a very genuine talk with him about how he exactly made you feel. That will melt any guys heart and possibly get empathy or even guilt out of him. Or even apologies.

If he cares about you at all that talk will work, if it doesn't he doesn't care about your feelings and you shouldn't either at that point. You could kindly tell him to f*** off.

That's my honest advice. Hope this helps.

Just sweetly say that you're glad he's so popular with women on FAcebook, but that really he should tell them he has a girl friend already.

Don't act angry, just let him know..watch the look of shock on his face!

Just tell him "don't be like that!"

I think you will move to the other city. He will go see you sometimes but he will be out playing on the side. Could be the "thrill of the hunt". It's nice to be desired. He might not act on any of it but use it as an ego boost. Either that or he's a dirty dog.

Good luck.

Her number is probably in his phone under some guys name. That's what I would do.

I think it was his phone, I think he is a cheater, you are a liar, and both of you are in for a wild ride.

Make a fake Facebook profile and start messaging him. Set up a sting.

As I see it he's done nothing wrong... At least not to you.. Maybe he should have told them so as not to get their hopes up or anything but it's not like he's cheating on you or anything
But if it bothers you you could talk to him about it, you could say something like "you left your Facebook open and I saw your messages... I see I'm not the only one who wants you... :)" and see what he says
Try not to show your jealousy though, it's not a good thing...

Not sure how your going to do this without confessing to looking, but if your OK with that, state to him that you had a right to look because its obvious he's hiding something, because its only bad to snoop if you find nothing to suggest good reason, so ask right out, why he feels he has the right to flirt with girls when surely he would have the raving hump if it was you doing it with guys?, there's your defence, don't let him get away with disrespecting you like he has,x

Tell him he's busted, leaving his fb open, and you need to know where your relationship stands.

Tell him that he left his Facebook open on your phone and that you saw how he replied to that woman and what she said about giving him her phone #. You also saw his response, with the "smiley" ...Be completely up front with him and let him know, you don't want him interacting with women like that. He's not single, he's with you, so the flirting with other women should stop or you're going to find yourself another boyfriend. Probably on Facebook. :

" I can flirt and play around with other men too, how would you like that? "

Set your boundaries and let him know you don't tolerate this garbage. Good luck.

If he's leaving Facebook open on your phone with these messages, he's asking to get caught. You should just ask him straight up what's up with the messages. From what you've wrote, it doesn't appear he's acted on anything so don't bring it up in an accusing tone. Just say something like, hey you left Facebook open on my phone and I noticed some girls gave you their number, what's up with that? Don't they know you have a girl?

I would dump him so fast his head would spin!