How to deal with ex girlfriend having a new boyfriend?

my ex girlfriend who claimed she still loved me and still had feelings for me even after she broke up with me, is now going out with an 18 year old(were both 16). she always told me she had no feelings for him and she never would. i spent about a month trying to convince her to come back to me and proving how much i loved her. (she broke up with me saying i didnt trust her enough when i did and was a good boyfriend even all her friends said that) so i dont know how to go about getting over her im still in love with her and mad at the same time for lying to me about liking this guy. help?How to deal with ex girlfriend having a new boyfriend?
Honestly, I bet she made up the whole trust thing just to have a reason to break it off with you.





It's obvious this girl has no interest in you, and you shouldn't interfere with her relationship with this guy...





It's kinda hard to tell you but, i'll say it because you need to know. MOVE ON. This girl has no interest in you and doesn't really care about you.





I'm sure you can do better.