Most Helpful Guy
It would be fair and selfless of you to address your change of heart about the relationship, especially if he is fully invested in the relationship.
Given the fact that you reached a point in which you are avoiding him and thinking of other guys, it is safe to assume that flirting and other improprieties will soon follow if you continue allow your curiosity to build.
Once that happens, he may want to disassociate him from completely.
To avoid mistrust from occurring and continuing or discontinuing on a sour note, I suggest that you be as forthcoming as possible.
But first, I suggest you spend as much time with him as you can, perhaps over a few weeks or so, to determine with certainty if you are unable to reach nirvana and fulfillment by simply being with him, and to determine if it's where you want to be.