First off, when I first started dating my current partner, I went through a similar issue. We were dating and it wasn't just the ex, it was girls he was talking to before we made it official. He even had his ex (who the DAY we started talking, he had just asked back out and she turned him down, and then a few days after it was official she changed her mind and he turned HER down) stay the night so they could get drunk and hang out, without me there.

Odds are most women would get upset and/or jealous over that, but I gave him the benefit of the doubt...

And now, she and I are best friends, I trust that nothing ever happened between them, and she talks more to me than she does to him. Both of their stories match up, and he told me nothing happened. Sure, it would be possible that she or any of the other girls he was around when I wasn't had actually had sex with him or that he's cheated on me, but I trust him.

That's not to say that in your situation he doesn't still want to be with the ex, or that he's not playing you behind your back, but that isn't always the case. It's all about the person. Just like when we were first together, I gave him the same benefit of the doubt I expected, as I hung out with my ex's, had a few guy friends over (though they didn't stay the night) and spent a lot of time with them during the week (when I couldn't see him because of work) just to hang out. I never did anything behind his back, and I expect him to trust me when I say so.

But...I will hope for you that it will work out and that you won't be hurt in the end.

Too much drama....

I would tell him to stop hanging out with his ex, end of story. If you don't like how you're being treated then stand up for yourself and say so. There should not have to be any kind of investigating or private detective work in a relationship.

I'm going to be honest OK?

I say get rid of him as fast as you possibly can. Run for your life. I know you may not want to hear that, but you've already gotten your kids involved with him you say? Well he's already showing that he you aren't important enough to him and he doesn't care any more than to use YOUR phone to call his EX?! Wow. I'd pepper spray his ass while breaking up with him. What I'm saying is he's clearly not mature enough, responsible or considerate of your feelings. He's disrespecting you and that's a nasty thing. But if he cares so little and you say your kids already like him, don't let him break their hearts too. It's not fair to them and he is not worth it. If he can't get over his ex then he isn't good enough for YOU. Not the other way around. He sounds like an immature pompous, arrogant SOB.

If you put up with this now then it will only get worse and he'll only walk all over you and disrespect you even more and quite frankly anyone who disrespects me is not good enough for me to bring around my kids and that is something that I take extremely serious. When it comes to them, no man should ever come first. Think about how he may decide to up and leave after you all are attached. He may not care enough not to hurt you all, but you have to. Kids don't deserve that kind of hurt. When a kid likes someone, they really like them and can get attached quickly and easily. They usually don't know pain like adults do. They usually don't know that people leave and never come back to see them. I'm just saying you really have more than your heart to think about and he's not good enough for your heart to break over, but realizing that your kids cuold get hurt too will help you make the decision you need. It is YOUR decision, but I just don't think any woman should allow this kind of treatment from a man.

I had a boyfriend years ago who I thought was serious about me and I eventually learned he was calling his ex and she started calling me and saying he was cheating on me with her. As stupid as he is, of course he swore it was a lie. I gave him one chance to tell the truth and I done some investigating of my own. I asked his ex, if she could provide proof. She then described the clothes he was wearing, the boxers I BOUGHT HIM! And the damn T-shirt I bought his sorry punk a**! I told him he tried making a fool out of me and that I was far too smart and too good for that and I left. After he was over her, he called me for 3 years straight trying to patch things up. I finally changed my number.

I hope you find the courage and strength you need to do the right thing. Sticking around seems like it will bring a change with time, but that rarely happens. I say the best thing to do is save yourself and your kids a heck of a lot of heart ache and kick him to the curb... and kick hard!

Hmmmm, unfortunately it sounds like he is using you as a door mat! He wants his cake and eat it too, but that wouldn't sit well with me.
If a guy is serious about me, he bloody better not go racing off everytime an ex calls.
Sounds like he doesn't want to give either of you up, but seems to me as though she is the top priority to him. He is swaying between the two of you, but if you are both wanting him at the same time, seems like she wins.

You can do so much better chickie
I know it's not going to be easy at first cause you have fallen for him - as well as your kids, but you deserve someone who will focus only on you and not every other girl hanging around.
Find someone you can fully trust!

You're the same person whose child sleeps in the bed, correct? I think that's really the crux of the issue here, not the ex. The ex is just a really convenient excuse. It's unfortunate, but you really can't expect someone who isn't in love with you to deal with those things. And as much as it hurts, I really don't think five months is long enough to be in love with someone (there are rare occurrences, sure).

In all honesty, my advice to you is to be very protective of your children and who they are around. Just because you're dating someone doesn't mean you have to introduce them to your children. It's so much harder for a child to understand why people come and go in one's life, especially if they like the person.