I don't know how to act around him anymore.

[lovemon]

The guy I have a fling with .I like him and I couldn't tell him that I like him , until the day I was going to tell him .I was him having a fling with another girl which is also my friend . The guy is my friend too and I don't know how to act around him anymore. When I am around him I get angry for no reason and I can't tell the girl (my friend that I also with him )

please what should I do

[SuitsAreAwesome]

Don't try to behave anything different, since that might give him the wrong impression. I don't know how long he's having a fling with that other girl, but if it was only the past week or so I wouldn't worry too much yet. I also wonder how long he did seem to have a fling with you. If he appeared to be interested more than a few weeks, then there's a good chance he still is. It would be really weird if he suddenly lost all interest in you for no good reason. Try to approach him when he's alone and tell him what you wanted to tell him earlier.

[Prof_Don]

Key question: did he know the girl he had a fling with was your friend?

If the answer is no, then he isn't as fault, cauz frankly a "fling" means he wasn't committed to anyone, therefore he can fling with who he wants to w/o any attachments.

[lovemon]

yes he did know that the girl was my friend