It sounds like your BF is cool with your having other relationships and just wants to be informed. I see no reason not to go ahead, as long as anyone you get involved with is made aware that you have a LTR. However, I do find your use of the word "experiment" a bit problematic. Personally, I would not want to be anyone's lab rat to experiment on, even if it was going to get me some sex. Just remember that anyone you hook up with, even if they have a reputation as a player, are real people with real feelings and they should be respected just as much as you respect your BF. So, don't experiment on them, just be yourself and be with them, and see what happens. Good luck!
The world opens up... when you do.
"Oh, oh, can't you see? Love is the drug for me." ~Bryan Ferry
"Love and the self are one . . ." ~Leo Buscaglia "