Is it normal i want to get back together?

So, I found out my boyfriend cheated on me while I was in Florida on holiday a month ago.
Basically, he went to a party at our friend's house, got really drunk, started chatting with his ex-girlfriend, then he kissed her.
I know it was only a kiss, but it was a kiss with his ex. Also, after my friend told me he cheated and I confronted him, I looked through all of his FB messages to her, they weren't flirty exactly, but they were friendly I guess. He asked her the next day while he was sober over FB whether he should tell me or not. She said it was up to him. He then replied with "Heh, I miss you more anyway, anyhoo, g'night!".
So, after all this, I broke up with him but for some reason I couldn't be angry at him because, as clichéd as it is, I really love him.
So, I ended up talking to him, he begged me to forgive him and take him back, he even cried and then we ended up sleeping together.
So, the being together but not being together has now gone on for a week or so BUT...
I was still angry at him, still love him but was still really angry and I had to take it out on something somehow. So I ended up going to my guy-friend's house and sleeping with him. Totally regret it now however. I thought that if I slept with my guy-friend that I could get back at my boyfriend and feel better. I realise now that was a completely immature thing to do and I awfully regret it so I have an even bigger problem.
My boyfriend/ex-boyfriend/whoevenknows is taking me out on a date tomorrow to see Ted (I've already seen it, was f**king hilarious, highly recommend!) however, he's basically told me that tomorrow is when he is going to ask for me back properly, all romantic n sh*t.
So, do I get back with my boyfriend and tell him I slept with someone else? Or do I get back with him and not tell him? Or should I not get back with my boyfriend at all? I really have no idea and need help guys. is it normal I even want to get back together after all this sh*t?

EDIT: He never told me he cheated, I found out through a friend, when confronted he told me he was going to tell me however I was going through a rough time recently and he apparently didn't want to "hurt me more".

Thanks x