He Dumped You:
In many cases, breakups come completely out of nowhere which hurt the most when you assumed things were fine. Whether it was immediately or after some time has passed he's moved on and you're killing yourself trying to understand why her and not you! If you only dated for a month or for as long as 3 years, this situation can take some time to get over.
You Dumped Him
For whatever reason, you felt it was time to go your separate ways until the day you find how much of a different person he seems with the new girl in his life causing you to rethink the mistake you made.
Ex Meets Next
Either you're at a party,random run in at the supermarket, or your basic cyber stalking the two of you now know each other passed word of mouth. Regardless of the two of you admitting it you "hate" each other and may hold a bit of jealousy too.
The Ex: For her to get to you means you still hold feelings toward the relationship and haven't gotten the closure you need to move on.
The Next: You're curious, and why wouldn't you be. You're very happy with your current boyfriend, but because things are still new you want to make sure he isn't holding any old feelings himself plus you want to know the difference between you and her.
When it Becomes a Problem: It's perfectly healthy to feel jealous,curious, or feel a little threatened However, this is not the time to attack each other. Whether he dumped you or you dumped him, that person made a choice they chose to move on. Technology makes it very easy to hide behind words we really want to say out loud. Do your best to avoid this. When all you have left are old ticket stubs and pictures when she has the real thing it can be hard to cope or when you're dating someone that means so much to someone else don't gloat about it.
1. Grieve! You're allowed to
2. Take it one day at a time. You'll get there
3. Keep busy! The more free time you have the more mixed emotions you'll feel deferring your healing process
4. Forgive: This one is the hardest to do, but it's the most important. As cliche as it sounds you were taken out of a situation you didn't belong in for a reason. Thank them for giving you a second chance to be where you really need to be and make peace with the parts that were good about the relationship.
5. Don't Hate: Before all of this she was just a girl with no ties to you a girl you probably could be friends with if you were'n't already. See her side of the situation instead of putting out negative thoughts towards her.
New Girlfriend's Job
1. Have the Talk: Talk to you bf about his past relationships (and yours) ask questions and see how he sells his response. If he sounds like the victim in most of his stories this might be a red flag. Regardless of what happened if they don't have anything nice to say about the person or seems hostile while talking about them means they're not completely over it. If he leaves you in the dark about most of his relationships that can be a red flag too.
2. Remember! There are 3 sides to every story His, Hers and the Truth. As the the new girlfriend you're going to take his side you're on his team not hers, but that doesn't mean what she has to say is total bs. Think back to when you were an ex. How many times have you thought to yourself "he's probably telling his dates I'm this psycho freak". No one wants to be the bad guy, but a mature person can admit when they made a mistake or can be honest as to what happened. Sometimes things just don't work out and is no one's fault.
3. Trust him!: If he's not giving you any sign that he wants to be with someone else let his past go. It's his past not yours. If a couple is truly happy with each other they are not worrying about what other people are saying about them because at the end of the day they know the truth. Don't pull your friends into it as if you're going to start an operation "kill the ex" war, for they don't know the whole story either. Be the bigger person and Just Let It Go! If he's not worrying about it neither should you don't give him an excuse to question you're maturity level.
4. Reach Out: This is completely optional, but it might benefit the both of you to try to be friends or at least understand each other. This is a must if he has children, since she is now going to be in your life. It's important to be civil towards each other. You're both human, and two girls who may have more in common than you think. What may have seemed like a torpedo aiming towards your relationship could be your next girlfriend.
Keep in mind, as the ex you have issues with him not the new girlfriend. He (or you) made a choice when they could have stayed together. No one can steal or force anyone to do something they don't want to do.We don't live in a supernatural world where a person can glamour someone.
As the new girlfriend ignore her, but put yourself in the ex's shoes for just a minute to realize she's just hurt and needs someone to blame deep down she doesn't hate you, she envies you which can be hard to admit. If you haven't been in this situation already don't try to get even because you never know when the shoe will be the other foot.