In point of fact, since the adhesion is much broader than your normal frænulum, whatever force is applied on retraction, is taken over a much greater area, so that you are quite unlikely to experience pain on retraction, and it is not going to tear readily.
Which is the point - it may be possible to separate the adhesion as I have described above, but it will take quite substantial pulling to do it. It is not possible to see from the photos just how possible it is to do so. After so many years (since childhood), adhesions may or may not be practical to separate other than by formal surgery, and that is in itself tedious and often unsatisfactory in my experience.
My best suggestion here is to see if it will separate, and if it does not, be content that this detail will not actually cause you any problems.