When she has a new boyfriend, things can turn real rotten. You probably cannot stop picturing them together, and absolutely hate the thought of another guy being so close to her. Emotions will cloud your judgement, yet it is still very possible to win your girl back, even if she has a new boyfriend.
When you find out she has a new boyfriend, your stomach is going to sink lower than it ever has done before, and your eyes will probably well well up. She is expecting this, and if you succumb then it could seriously damage your chances of having a successful relationship once more. Things can take an unexpected turn for the worse if you show emotion-she won't magically realize how much you love her and dump her new boyfriend, so don't bother with it. There are better ways to go about getting your girlfriend back, even if they are rather counter-intuitive.
What I am going to teach you is known in the seduction community as a 'boyfriend destroyer' – a way to get rid of-yes, you guessed it- her boyfriend, it is achieved by making him look like a beta male. If you are naturally alpha then it should not be difficult, however here is a rough guide.
First thing to do is accept and agree to the breakup, which will put you in a position of power and control that secretly makes her feel like you broke up with her.
Second thing to do is make her new boyfriend seem like a nice guy. Girls are not attracted to nice guys. Thankfully, it will only seem like you are giving her new boyfriend your blessing. Tell her 'I don't think he would come out on top in any fights, but he seems like a real nice guy.' That is giving him your blessing, but really you are telling her 'he is a proper, bona fide wimp. You are with a loser. '
A bonus to giving her boyfriend your 'blessing' is that she will start questioning your motives. She totally expects you to still be madly in love with her, and showing your disinterest in her by telling her what a nice guy her new boyfriend is will have her questioning your feelings and motives. This then transfers her emotion and thoughts onto someone other than her boyfriend, and just to make that even better: that someone will most certainly be you! This method can work wonders for when she has a new boyfriend.
