Plain and simple, it's because this is what's on your mind. There isn't a real psychological thing, in a way. The main reason that you're dreaming about your ex and his new girlfriend is because it's what's bothering you most right now. give it a few weeks and you'll get over it.
get over it and move on
because you miss her a LOT !
The significance of dreaming about your ex-girlfriend basically means that you are still thinking of her.
She probably did it to make the ex- boyfriend jealous.
You should be confronting your ex and telling him you do not like his girlfriend asking your children about your new boyfriend and if it keeps up he will only be able to see his children at your home or without his ex girlfriend.
you should find a new bf
A girl should never fight with her ex-boyfriend's new girlfriend. The girl should move on and let her ex and his new partner do the same since fighting will not solve anything.
It may mean you still have feelings for him and so are worried about a situation in which it would be hard to get back together with him. It is okay that you still have feelings for him but also move on to.
find a new boyfriend or girlfriend to stop you thinking about them ( your ex )
You do absolutely nothing about your ex boyfriend considering he has a new girlfriend. If he loved you he would break up with his girlfriend and since he has not then he wants to be with her and you need to accept that. Just because you have broken up with your boyfriend it doesn't mean you can just step back into your ex boyfriend's life.
Simple Answer: You don't.
Dreams often reflect our subconscious thoughts and feelings. Your dreams about your boyfriend's ex girlfriend could be a manifestation of your insecurities or concerns about your relationship. It might be helpful to openly communicate with your boyfriend about these feelings to gain clarity and reassurance.