Intellectual debates are hindered from their purpose, which is to search for truth, by feelings and personal sentimentality.  

If a person has serious reason to believe they're not actually married to the person they're living with, I don't think doing nothing is an option. They need to either ask the Church to regularize their situation or seek the declaration of annulment.

With so much chaos in the Church, a woman can ask 10 different priest/bishops and get 10 different answers.
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Rome rubber stamps all annulment requests. 
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I don't think either if those are good options.
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Some women in these circuмstances choose to stay.  Some women choose to leave.  It is whatever God calls them to do and we can't fault either choice.  God knows her heart.
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Intellectual debates are hindered from their purpose, which is to search for truth, by feelings and personal sentimentality.  

I was on another Catholic forum called Archbishop Lefebvre Forum some years back and was set back on my heels at the reaction to a couple of threads of mine about female hair length and a proposition that Archbishop Lefebvre Forums have two separate forums for men and for women. I posted to see if I could ferret out any feminism on the board, thinking maybe one or two people might put me in their crosshairs. Almost the entire forum turned on me, with a fake seer who went by the handle DawnMarie (who actually knows Bishop Williamson) and her coterie leading the charge. It was especially strange because I thought most of the people on that forum were less infected with feminism than myself. And this was a forum where I was on good terms with at least half the members, the admin and (at the time) the two ineffectual mods Mithrandylan and TMW89. The men on that forum were afraid of the women on that forum. It was a pathetic display.

I didn't read any of the threads Croix started about feminism, but he couldn't have helped himself by using that black preacher to back up the points he was making. He was giving people who are infected with feminism a get out of jail free card.
I don't know for sure if the nature of a coed forum makes for a breeding ground for feminism, but it's possible. Since feminism is Marxism applied to gender, traditional Catholics also have a problem of being Judaized.

When I've seen this scenario, it has more to do with an unhappy marriage and a spouse trying to find a way out. He/she usually doesn't really have concerns that the marriage is invalid, but rather is wishing that it was! (Or, even more likely, they left / were left a long time ago and have now found a new person they'd like to marry.)
Can you elaborate with an example? I can't think right now of a marriage impediment that a spouse thinks might exist that couldn't be resolved to ensure that you are indeed married. If you really think that your marriage might be invalid and decide not to pursue a declaration of nullity, wouldn't it make sense to resolve the doubt by instead re-affirming your marriage vows?
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This raises another question for me. Say, for example, you think your marriage lacked true consent because it has become apparent that your spouse never intended to have children. Wouldn't it be sinful to ignore the situation and go on living like a married couple when your marriage was likely invalid?

I would think so, if you have doubts about the sacrament received, it’s sinful to ignore. same applies to Baptism, Confirmation, Holy Orders, hence why they are given conditionally. Marriage is a state, and to act like you’re married when you’re not would be a sin. Better safe than sorry 

Almost the entire forum turned on me, with a fake seer who went by the handle DawnMarie (who actually knows Bishop Williamson) and her coterie leading the charge. 

Ah, so DawnMarie is still floating around?     Has she had any more visions/revelations?

I know.  I've called this out once before.  I know a couple extended family who pulled the old "conversion" marriage.  Both had their wives leave and divorce them.  If I were a priest, I wouldn't do these at all.  If the prospective spouse converts after marriage, that's fine.  Very few such pre-marriage conversions are real and sincere. 

I became Catholic while engaged to my husband-to-be.  My conversion was real and sincere, although, due to the horrendous Novus Ordo instruction I received, I was incredibly ignorant about the Faith.  For example, I thought that private Confession had been replaced by group Reconciliation services and did not even know how to go to Confession.  I thought that the Rosary was from back before people were literate and someone like me had no reason to pray it.  I thought that birth control was up to the conscience of the couple. Etc.

So, to a large extent, I did not even know what I was converting to.  About the only doctrine I understood correctly was that the Eucharist is really the Body and Blood of Our Lord.  I knew this because I had learned about it in a high school history class, not because I was taught it at the Novus Ordo.

I became Catholic while engaged to my husband-to-be.  My conversion was real and sincere, although, due to the horrendous Novus Ordo instruction I received, I was incredibly ignorant about the Faith.  For example, I thought that private Confession had been replaced by group Reconciliation services and did not even know how to go to Confession.  I thought that the Rosary was from back before people were literate and someone like me had no reason to pray it.  I thought that birth control was up to the conscience of the couple. Etc.

So, to a large extent, I did not even know what I was converting to.  About the only doctrine I understood correctly was that the Eucharist is really the Body and Blood of Our Lord.  I knew this because I had learned about it in a high school history class, not because I was taught it at the Novus Ordo.

You were taught those things in RCIA?
What decade, 80's?
Scary!