So, I've known this guy for like 5 years, but in the past 8 months we have only started talking properly. Every since I met him, I had some feelings for him, but he went out with my best friend (at the time) so I knew nothing was going to happen. But since we have started talking my feelings for him have grown, the only problem is, he has a girlfriend, but it is a long distance relationship, she lives in another country so they never really get to see each other. But we started talking a lot more, he always tells me that I'm better than all the other girls he knows, also when were not even talking he just sits and stares at me sometimes. Recently we started meeting up more, normally after a stressful day I will go on a walk on my own and he found out that I go on my own and said that he was worried about me going on my own and said he'd come with me and ever since then he has, every time we go on these walks he's always touching my shoulders and he walks me home even though he lives quite a bit away from me. He even joked about having sex with me but said he wasn't lying. But I don't know whether he likes me as a friend or something more. Him and his girlfriend aren't going to last he told me. But does that mean there's hope for me.. should I tell him I like him and see what happens from there (obviously when he is single I wouldn't want to be the cause of his break up) I'm not really sure what to do.

So long as he is in a relationship he's not available.

Sounds to me he is willing to cheat on his girlfriend,not very attractive a trait,do you think?

Dump him.

He has a girlfriend which makes him off limits.

He is manipulating you into having sex without him breaking up with his girlfriend by telling you they are not going to last much longer.

If that is the case then why is he still with her? When you know it is over why not end it?
Because he has another agenda , to have you when he is there, and her whenever he gets back to where she is.

You should tell him that when he has ended his current relationship and had sufficient time to heal, then you will consider going out with him.

My thoughts are that he has no intention of breaking up with her and wants to have you on the side.

And right now he is cheating on her with you. His actions clearly say he is working on having sex with you while he is still with her.

If you did get together could you trust someone you know is a cheater?

It is hard to turn down flattering attention. And we all want to believe what we are told by someone who has sparked our interest when what they say is going to be beneficial to our hopes.
This is how so many people get their hearts torn out.
In these situations you get blinded from reality by the attention , and soothed into losing your foresight by the lies .

Stay away until he is no longer in that relationship.
Then stay away because he is a cheater and manipulator.

Usually they never change their ways ,they only change partners as they use them up.

I don't know an easy way to say this but he clearly doesn't want anything more then a booty call. If he really liked you he wouldn't string you or his girlfriend along and be with you but since he hasn't made an effort he isn't going to later on.

I can't stop thinking about someone, and no matter what else I do something always reminds me off them. How can I get them off my mind?

Stop being around them and get busy doing things you enjoy with other people. Over time, your feelings will fade to the back of your mind because more important things will replace this fellow.