Hey Cali. If you have standards for restoring trust, 100% transparency (like unblocking on social media, access to his cell phone at any time, etc.), and/or a boundary about any future evidence of affairs (and usually the boundary seems to be "no more affairs or I walk") then I would further explore this issue. Otherwise, the standards and boundaries aren't meaningful. He feels no consequence from breaking it or avoiding it, especially since it sounds like you've given him more than enough room to come 100% clean so that the two of you can move forward, if possible.
MWD has a newer book on healing from infidelity. John Gottman has a chapter on it in "Making Love Last" so it might be helpful to read up on what their research has found to be effective practices for navigating affairs and restoring trust. To me, this is also hard work without a MC involved. And, partners may make mistakes (like you suggest about him being potentially afraid to tell you) because their judgment about how to make a relationship work needs rebuilding.
