I had my gallbladder removed 3 years ago, is there a possibility that the stitch on the inside has opened after all this time?

Possible; Relevant?: Unlikely. Why? The purpose of sutures=only temporary: hold tissue in close approximation, allow more rapid healing into the goal new organization. After days-to-weeks all the strength is within the tissues, not the sutures. [For a variety of purposes, resorbable sutures are used which dissolve (eaten away by macrophages) within a few weeks to ~3 months.] Afterwards suture=only a foreign object.