Bad Break Up

Recently I've dated someone who I really thought was going to be the one. I never had anything good before and he just did all the right things and showed me a new world. He had restored my faith. We really had something special.. at least I thought so. But then he broke up with me and wanted me to stay by his side while he went off talking to some new girl. I didn't want to break up in the first place and was fighting for our relationship when I saw him flirting with this girl publicly on social media and well.. you can just imagine how embarrassing that felt because he couldn't even be real with me he made it seem as if he needed some time to work on himself. Now I know it's a load of bullshit. He even tried to have sex with me again after everything but ignored how I felt, told me his feelings changed, that he's falling out of love with me and didn't wanna get back together etc. Honestly the whole situation drained me and I just want to know how to move on..