There are things to do so your ex wants you again
It seems like the ultimate horror, but don't panic. I'm going to tell you exactly what to do if your ex is seeing someone else. The first thing to do is convince your mind that this is a good sign - because it's true.
Your ex, like anyone else has a comfort zone that he or she wants to operate within, so excuse your ex if they want to keep things as normal as possible. In this case, "having someone to date" is the norm. Your ex is seeing someone NOT because he or she is in love with someone else already but because he or she is trying to get over you. Knowing this puts you in the driver's seat.
It's not rocket science - the easiest way to get over someone is to date someone else. This is the case also if he or she is living somewhere else. So your ex is smart just like you and is not used to being single. So what is your ex going to do? That's right...date! But trust me, rebounds never last. They serve a simple purpose. That purpose: to help someone get over their ex.
So don't mope. There's no need to. There's no sense in perpetuating your depression, especially because your depression might even be stemming from something that isn't real. I'm willing to bet that you're inventing all sorts of scenarios and false beliefs in your own mind. Your overactive imagination is likely painting pictures of your ex and the rebound living this glorious life and doing things you've only dreamed of. You must resist letting these self-created thoughts bother you.
Don't be aggressive and flip out at your ex for being insensitive. Don't decide that the only way he or she can be dating someone else is because your ex was obviously cheating. Don't apologize thinking it's YOU caused this break-up to happen, and if you did do something to sabotage the relationship, don't apologize more than once.
Stop making promises that you'll change or mold yourself into someone that you're not simply to get your ex back. You can offer to work on aspects of yourself in order to promote the health of the relationship, but don't reinvent yourself thinking it will fix things. In fact, your ex might not even want those things. By dating the opposite of you, it makes it easier to be without you; but that's not necessarily what your ex is looking for.
Golden rule: don't beg. It's a break up mistake. Draw the line before things get to this point. That is what to do if your ex is seeing someone else.
And if you find yourself at the point where you want to beg, take a deep breath then invest in my book Bait Him Back or Bait Her Back. The answer to what to do if your ex is seeing someone else is to make a solid investment in resources that will give you the logical and proven help you're looking for. My book has a wealth of resources, tips, and techniques that will make getting your ex back easy. Help is right here.