My experience with annulment:
I got married when I was 19, and the relationship quickly escalated in abuse. I was raised that marriage is a forever thing, so was prepared to try to "fix" things and live with this man (boy) forever. I prayed, worked, cried and became increasingly depressed and spiritually numb. After 3 years he came home from a trip, told me he had fooled around with some girls, and realized that he "missed out on partying, dating, and having fun."

Part of me was heartbroken, and a part of me screamed "run!" So I did.
My parents asked me if I would consider getting an annulment. I thought I couldn't possibly put myself through the process and was skeptical about whether my situation was applicable. I consented to talk to the annulment councilor in our diocese. She was the sweetest most beautiful nun I have ever met, and it was actually a wonderful experience. Since I didn't have an agenda, and wasn't looking for an anulment I just told her what life had been like, answered her questions as honestly as possible and tried to paint an accurate depiction of my life. She told me at the end that she rarely gets people in talking about what they did wrong in the marriage, and that a lot of finger pointing and embellishment is common, and that she was very touched by my honesty.
Then I had to give her names and phone numbers of my spouse, 3 witnesses and various family members on both sides.
I then had one more meeting with her, where she talked about her findings, talked to me some more, and then sent everything on (all of the documents and recordings of our sessions) to a tribunal of priests. I didn't really think about it after that, and almost a year later, got a letter saying that based on the evidence provided and prayerful consideration by the tribunal I was being granted an annulment. The reasons were that my (ex)spouse admitted that he never ment to keep his vows, never had any intent of staying in the church or raising our future children in the catholic faith, and our young age. It was determined that Christ was never a part of our marriage, meaning in the eyes of the church we were never married at all.
This experience was actually painful in the end. Reading that a group of strangers have deemed that Christ was never a part of your marriage hurt me. I have now come to realise that Christ was not allowed to be a part of our marriage, in the way that all marriages should be a trinity. Now that I am married to a man with a relationship with Christ, I understand. Both parties have to welcome Christ into their relationship, and I believe that the "head of the house" spiritual headship role that is my dh's responsibility is to keep that trinity healthy and thriving, so in my previous marriage, the actual breakdown was much deeper than I had perceived.
Did that ramble make any sense. That's the first time I've actually talked about my annulment experience.