He used me to get her attention

Girl A is together with boy B for 4 years in total. B moves abroad for uni to pursue his dream career. A breaks up with B after about 1 year long distance. B feels blindsided and devastated. B no longer believes in love. B is single and focuses on his career, fitness, hanging out with friends, partying etc.

B keeps this up for about 4-5 months and then meets girl C (me). B approaches C, they start talking and dating. B tells C about his ex and that he had given up on finding someone else until he met C. B love bombs C. C is overjoyed about experiencing “love” for the first time in her life. B asks C to be his gf. C is super happy. B introduces C to his friends. C introduces B to her friends. Everything seems to be going great. B tells C that he is falling in love with her. C says that she is feeling the same way.

B, without telling C, texts his ex, A to share the news that he has moved on????. B and A starts texting and B starts acting more cold toward C. C notices text messages from A next time she is with B and starts a conversation with B about it. B tells C that he texted A and that A wants him back. B says that he is confused about his feelings but that he has always felt that there’s something holding him back from going all in with C like he did with A. C asks B not to compare her with A and tells him that he cannot be in touch with A if he wants to be with C since it’s clear that A is holding him back. B denies this and says that A and B are friends and that C is being controlling.

It ends like this. B breaks up with C saying that he is not ready for a relationship, he rushed things with C and that he is chosing neither C or A. He then gets back together with A.

I don’t really know how to deal with this. It’s been quite some time and I’m still devastated. I think they are both in the wrong (her for wanting someone taken and him for absolutely everything) and have a hard time accepting that they get happy ending and I am the only one who got hurt in this. The way the guy switched and completely changed when his ex came into the picture also terrifies me. Please help