What should I do if my family figures out that the eight characters don't match? I don't want to let it go. I've been talking for four years.

If you have a good relationship when you are together, and there are no other substantive problems, then you should not break up immediately because you understand the disagreement. The eight-character algorithm can be used as a reference and guidance, but it is not intended and will not affect your real feelings and life. You can try to communicate, share your own views and ideas, and discuss how to solve the problems you encounter together. Of course, if there are other major differences and problems between you, then you may need to seriously consider whether to continue together. In any case, the most important thing is to believe in yourself and each other and try to manage your relationship well.