I've been speaking to an incredible guy for half a year now. But I'm not sure if he's lost interest in me?

So, yes, I've gotten to know a guy not much older than myself over a period of seven months, going on eight. Our shared love of animals and reptiles, our cute playful arguments over Ford and Holden (YEAH HOLDEN!) even our shared love I'm hip hop music (EMINEM!) When I first met him, he did have a long term girlfriend, yes. But he rarely ever spoke about her, and he always seemed genuinely thrilled to see me, as people we associate with have told me. After drunkenly opening up to my best mate about having feelings for me and how he would never hurt me, he did repeat the conversation to me. And after that, we grew even closer, speaking daily on snapchat and text, sending me cute drunken texts. He'd visit me and work, pick me up from the cinema and drop me off at work which was a legitimate two minute walk, because he didn't want me walking in the dark.
We've always said that we would like to hang out even more, but lately it feels as if he's losing interest in me as a person, and I can't stand that were not talking as often, if at all. And after an emotional week, I shed quite a few tears over this boy, he means quite a lot to me, and I'm not sure what is going on… Help?

He's also spoken about his ex, personal things that just ticked him off, I'm not willing to share as they're not mine to share… But afterwards as I have him advise, he told me exactly why he liked me…

If he's a rude, selfish, hypocritical, inconsiderate, condescending, stuck-up bad boy, dump him or reject him and tell other girls to avoid him!

There could be something very heavy going in his life. You have known him for almost 8 months. And then all of a sudden he has become distant and seems to be pushing you away. You need to talk to him. You need to tell him that it's important to you that you talk to him. You need to ask him to meet you in person. Go for a coffee somewhere so you don't have to rush to talk. And don't be afraid to ask him what is really going on with him. You need to remind him of all the good times that you had and that you can't understand what is really going on with him. Is it possible that he's fallen in love with you? If he's still with his girlfriend then it could be possible that he's trying to figure things out. But you will only know what is really going on with him once you talk to him. You have a right to know. You need to know where you stand with him.