What you're wanting to do is very common not only with a breakup but with getting over an addiction of any kind. You're trying to talk yourself into going back for one more drag of that cigarette, one hit of that H, one pill of that prescription pain drug.
You're going through withdrawl from not having him in your life and getting one hit of him every once and awhile is not going to help your pain. In fact, all its going to do is keep you addicted and continuing to cause you pain with each little detox you have to go through.
Give yourself some more time to get to the stage of indifference to him. That may take a month, a year, even two years if you don't do the mental work you need to do to stop thinking about him, to stop trying to look nice for him (do that for YOU, not him).
I congratulate you on being with enough self-love and good personal boundaries to not settle to be demoted from lover and friend to just friend. That would have been even more detrimental in you rehabbing from him being in your life.
Remember this: You can't quit smoking if you keep having a drag off of a cigarette. Just like you'll never get over him if you keep letting him in your life.
You'll be fine in time and how you're keeping busy using your time... I promise. You're with enough self-love, self-respect and self-esteem that I can say that without doubt.
“The willingness to accept responsibility for one’s own life is the source from which self-respect springs.” ~Joan Didion