Here's the hard pill to swallow, which has caused many to leave the Catholic Faith (see John chapter 6 -- apparent disciples left Our Lord and "walked with Him no more" because "this saying is hard, and who can hear it?")
A bad marriage, or a miserable marriage, or a lonely marriage, is not something you can dissolve or make disappear with the wave of a magic wand. Even the Church can't "help you" here.
One partner forcing the other into a sexless marriage for example. As long as the marriage was consummated, especially if you have one or more children, then the right intentions were assumed to be there at the outset.
Things falling apart, things going bad, spouses growing apart, one/both spouses becoming miserable -- none of those things mean a marriage never took place. They only mean a marriage has gone horribly wrong, you have a BAD marriage, but a marriage nonetheless.
Remember, an annulment is NOT Catholic divorce! There are many reasons non-Catholic couples get divorced -- each divorced couple sought to dissolve or break up a "bad marriage", a marriage where things went wrong, and one/both spouses are unhappy. Usually so they can try again for "happiness" with someone else.
We must not confuse these two concepts!
Often one or both spouses enter into a marriage with vague expectations of the future, that they never voice or barely know about themselves. For example, how much they expect to be earning in 10 or 30 years. What married life will be like. How many children they will have. Precisely what will be required of them, in raising their children. What challenges they will face. What kind of status the man will have in 20, 30 years. What retirement will look like. And so on. There might be differences in EACH OF THESE THINGS if you could somehow X-ray each spouse and look into their deepest thoughts. But such a thing isn't possible. These discrepancies are the seeds of future disagreements and problems. But they don't invalidate a marriage.