Length of marriage is not a factor. The conditions at the time of marriage are. My parents were married only a short time, had been divorced for almost twenty years, my mother is not Catholic and could have cared less (but she did fill out the forms they sent her) and they denied my father's petition.
After 34 years and seven children I am amazed anyone can honesty remember the conditions at the time of their marriage.
Sometimes I forget the names of my clients and have to wing-it for a few minutes when they call me; before it pops into my head.
Can anyone remember 1979? JP2 was the new Pope and I was playing Atari Space Invaders with my brother and bought myself a pair of Nike training shoes for running which none of my school friends had ever seen. That's about it.
If valid marriage is a contract between two people then the length they remain together should have an implication on the validity. If two business people had been sharing profits for 30 years and then went before judge and suggested there was never a contract; he would laugh them out of court. A contract would be implied by the length of time they had been in business.
The only way I could see a 34 year marriage with 7 children being invalid is if there was an objective impediment, like a prior marriage, or one partner had spent 34 years chained in a basement dungeon.
Asking two biased people at least one of whom wants to split, how they felt 34 years ago and basing a decision on that is just silly.
How old were they at the time of the wedding?
Is it concievable that one of the parties could have felt coerced to go through with the ceremony?