<human>: Can you give me a shortened version of the text?

My ex and I have been broken up for almost a year now. We dated for 3 years. Since the break up we have still acted like we've been a couple for most of it (talking everyday, saying i love you, sex, hanging out, flirting, etc). The only difference is that we have not technically gotten back together. There has been lots of different times when he would want to get back together and I would want to as well. Then he would proceed to break my heart and tell me he didnt want me. This has happened a few times already. Im pretty numb to the situation now. All he does is hurt me and treat me like im nothing so i try to focus on everything else that is going on in my life instead of all the hurt.

Now about his friend. Theyve been friends for about 6 years now and I've also known  him for that time. My ex and the friend used to hang out lots but not so much anymore because now the friends is going to school in a different city. This year i have recently transferred schools to the same city as the friend. The friend and i have a class together and have recently started working on the assignments together. lots of late nights and early mornings and i think we've actually gotten pretty close. My friends (also know the friend) think that the friend likes me. they Remark on how he always asks for help on the homework even though he's very smart and capable and can clearly do it himself. I hadnt really thought about him in that way before but now im beginning to. he's nice and funny and handsome and everything feels very natural with him. 

The problems are that:

1. I dont know that i can do that to my ex. My ex is a dick and has hurt me so much. He doesn't care about me or my feelings. I know if he had the chance to date any of my friends he would. so why do i feel horrible about even getting close to one of his friends?

2. Ive been in a relationship for so long i have no idea how to casually flirt with this friend without being too forward and scaring him off.
<bot>: My ex and i have been broken up for about a year. Im developing feelings for one of his friends. No clue what im doing. Advice?