OK, so here's some background: I used to live in the south, but due to my military career I was forced to move. When I got here I met a really sweet, super beautiful girl, and we started dating. We had only been dating for about two weeks when I took a vacation trip back home, while down there I bumped into an ex and we ended up sleeping together. When I came back I decided not to tell my girlfriend because to be honest I wasn't even sure how long the relationship would last. That was almost 3 weeks ago. Since then I have discovered how truly amazing this girl is and have completely fallen in love! But today my ex called and said she might be pregnant. I so don't want to lose the girl I'm with, and would do anything in the world to take it back, but I can't. So how do I tell my current girlfriend and not break her heart, and maybe even keep her?

I would not think about saying anything until you know for sure the other girl is pregnant. That would be too much stress for anyone to handle. Once you know for sure, than you may be able to broach the subject.
Then of course you will have many other decisions to make.:)

You have to tell her, and hope she has mercy on you. I doubt she will but it's the risk you have to take for doing the junk you did.

Going out with the ex while dating another girl for only 2-weeks isn't like cheating on someone you've had a long-term relationship with. In my book, dating someone 2 weeks barely qualifies as a relationship at all.

It's unfortunate that your ex may have become pregnant, but I don't think it's the end of the world. Since you have dated this girl another 3 weeks and feel like it's developing into something more serious, I think you need to tell her what you've told us (but only after you find out the pregnancy is real). It would be better to tell her now while the relationship is still young, than to wait until you deeply love each other. Believe me, it would be a terrible fatal blow for her to find out months down the road that you kept it from her.

If you can't stand up for what you do, don't do it.

Having said that, and not to be harsh, no matter how it turns out, do the right thing for yourself, AND HER, as it will never get easier, and its going to hurt her a lot. Sorry, no way around the pain. But you can at least give her a choice now, before things get deeper.

All you can do is be honest, tell her what happened, tell her your fears, and lay everything out in the open. This is a new relationship and you have a 50-50 chance for that "staying power" that will make it through this.

Be honest and leave it in her hands. You really only have one shot at this... honesty, complete forthrightness, and hope for the best.

If, on the chance that she decides she can't deal with this, you must let her go and learn from this.

I wish you the best of luck.

Karma always comes around and bites you in the A$$ doesn't it? I think it is so funny, that a cheater always thinks about why it was wrong to cheat, AFTER he has been caught or someone ends up pregnant. I surely wish the cheaters would think before they act, but I guess that is asking too much. In your case, you should be honest with her, and if she believes in you, you may be granted another chance, but I have a sneaking suspicion that this ex of yours will be popping up again, even if she is pregnant or not.

You had only been dating the new girl for 2 weeks. That is hardly enough time to be in a serious commitment with each other. I presume that you dated, but I doubt that you talked about being 'a couple', or wanting a long-term relationship, marriage, a future together etc.

If you did pack all that in in 2 weeks, then you sleeping with your ex was a betrayal in the worst degree.

If you were casually dating her without a commitment to more that just dating, then I would not say a word, until you know if your ex is actually pregnant, and that the baby is yours.

If it turns out she is pregnant, then it would be time to say that when you first met her (the new girl), you had travelled to your home town, and ended up having a one night stand with your ex. Unfortunately she got pregnant.

And then you'll need to step up, be a father, provide support, and hope that your new girlfriend will hang in there with you through the trouble spots you are sure to have, ahead.

Just a little update, I ended up telling my girlfriend and she forgave me. Turns out the ex was making it all up just to try to get me back. But I am proud to announce that after a month and a half of the most amazing relationship of my life. My current girlfriend IS carrying my child. For all you critics out there, yes I know it is quick and it was not on purpose but it is happening so I am going to make the best of the situation god has put me in. thanks for all the advice: in the end honesty is the best policy

Wow. This has red flags all over that can be seen even 2,000 miles away! Wishing you the best anyway! Emopunk7.

Make sure you both work on being the best possible parents. Having a child together is a lifelong commitment to that child.
Honesty is indeed the best policy,so stick to that-always.
All the best and take good care of each other and your baby.

You can't.