Seeing an experienced surgeon especially since you have had two failed labiaplasties is prudent. The revision labiaplasty in my opinion was probably done a little too soon. I would wait at least 6 months or more prior to revising a surgical result to allow enough time for the tissues to settle down . Visit with a labiaplasty surgeon who can examine you and discuss your options with you.
Indeed a revision can be done, but indeed it may split open again if just repaired in the same fashion. However, only after consultation and physical exam to assess the current anatomy and quality/quantity of remaining tissue, can the best surgical plan be advised. Glad to help.
I have not had a major separation in over ten years. I reconstruct many women like you who have had separations after wedge labiaplasties done by other surgeons. I would not reconstruct you until you are at least 5-6 months after you last revision. If you are done too soon, the chance of separation will increase. You need to be patient and let the swelling go down and the tissues to heal. A revision is often more difficult than the initial operation, so be patient and make sure you have a very experienced surgeon. I have not had to revert to a trim to repair these patients.
One of the most common complications after a wedge labioplasty is dehiscence [coming apart]. Also, once this occurs it has a higher chance of recurring. Generally when a wedge labioplasty is done, it is important to preserve the mucosa [internal tissue] or this may result in dehiscence. In your case, a revision can be done that you have to understand that this may break apart again. Another possibility if you have adequate labial length is to perform a trim method, to completely excise the dehisced tissue. It is difficult to completely see a question without seen pictures.
Wedge labiaplasty has a much higher risk of coming apart then the trim method, which is why I use it only very rarely. Without seeing pictures, it is difficult to comment, but I wonder whether or not too much was removed so that now there is excessive tension on the two sides of the wedge and that is why it keeps coming apart