I have read that one should not have any material between one's tefillin shel yad and one's arm (e.g. bracelets, wristwatches). I always wear a wedding ring on the fourth finger of my left hand. I was taught to wrap the tefillin shel yad strap twice around my third (middle) finger, then once around my fourth (ring) finger. That means that the ring is between the strap and my finger. Is this permissible?
Somewhat related: Red string on Tefillin arm?