Your boyfriend has made me so angry!
If i had one like this i would have left him as soon as he installed the app and started chatting to girls because i deserve better. He isn't taking the relationship seriously. He is literally taking you for a mug because he knows that you hate him on it yet he goes and reinstalls it? omg!! Does he care about you at all? I don't care how long i'd have been with the boy for or how much of a prince charming he once was, he clearly does not gaf anymore.
I know you are holding onto all the memories but i read some quote once on tumblr and it was like:
'how do you know its over?'
'when you're more in love with the memories than the person...'
Bless you because you want to hold on to what you both once had but people change and you soon see their true colours. I don't know why your boyfriend is aware of your feelings towards him having that app yet still uses it omg. I mean you saw yourself that he was asking a girl (which you were pretending to be) to meet up with him when he has you. You should be enough for him or else why is in a relationship? You shouldn't waste your time and love for someone like that. That behaviour is just disgusting! He clearly does not care about your feelings and clearly does not cherish this relationship at all when he is talking to the other girls and wanting to meet up with them. That is not a boyfriend. That is not commitment. I would literally call it cheating - if he is flirting with girls and asking to meet up with them. And knowing how you feel about it, it is as if he chooses it all over you. Does that not say something?
You deserve more. Who cares about the memories you once had when these are the kind of memories you will be crying over one day when you find out he has gone and cheated on you. Leave now, be the bigger person. There is someone out there who will love you and cherish you and treat you like you're the only girl in the world (did not mean to quote a song). Why are you searching for that in him? Hun, just let go because from what it seems, he is letting go already.
Dump his stupid ass and one day he'll realise. Go find some hot guy who worships the ground you walk on because you deserve that, you really do.