I helped a friend of mine fill in her passport. She's been married 4 times and it was getting very complicated trying to put together all of the relevant marriage and divorce certificates. We eventually decided simply to 'forget' two of her marriages. It didn't cause any problems.
The important thing is to provide documentation to show that the person named in the application is the same person named on the birth certificate. Here's an example:
Jane Smith marries and becomes Jane Brown. She later divorces and reverts to using her maiden name. She then re-marries and becomes Jane Wilson. It won't matter if she omits to mention her first marriage when she applies for a passport because her current marriage certificate will show that Jane Smith (the name on her birth certificate) got married and is now Jane Wilson (the name on her passport application).
However, if she had continued to use the name Jane Brown after her divorce, she would have to include details of her first marriage with her passport application. Otherwise the passport office would see a marriage certificate saying that Jane Brown got married, with nothing to connect the applicant's name to the name on the birth certificate.
So, if you can provide documentation linking the name on your birth certificate to your current name, without mentioning your first marriage, the passport office will be satisfied. You'll only have to mention your first marriage if it's necessary to fill in a gap in your chain of name changes.
Chris