Talk to a traditional priest.
If you don't have traditional grounds, stop right there and go no further. As I understand you can only permanently separate if both parties agree or if there is a sin which one party will not stop (infidelity, abuse, etc) which directly affects the marriage.
If you have traditional grounds, you can file for annulment on NO grounds (they can and may be different). But if you do not ever attend a diocesan church (even fssp) they may not help you easily. If you attend only sspx, it is complicated.
Only Rome can grant an annulment. No one else.
As I said, the Church holds itself out as being able to pass judgment upon the validity of any marriage.
Even if you got a diocesan tribunal who regarded you as being schismatic, unless they just wanted to spite you for being a traditionalist ---
"oh, so you really want this annulment, coming hat in hand to us, are you?" --- ideally, it should just be a matter of saying "here's the putative marriage, let's evaluate it".
The way I heard it, hypothetically (though this would never happen in practice), two Jews or two Buddhists could walk into a tribunal, with previous marriages, and could say "can you make a judgment on whether we are free to contract what the Catholic Church would regard as a valid [natural, non-sacramental] marriage or not?". Again, this would never happen, nobody would ever do that, but theoretically, they could.
Topic: Is There a Legitimate Way for Trads to get an Annulment? (Read 25615 times)