In The Story of an Hour, how "free" was Mrs. Mallard before she knew about the train accident?

"The Story of an Hour" is one of Kate Chopin's most anthologized short stories. As with most of her work, it focuses on the plight of women and how they are very often held captive (essentially) to the wills of the men in their lives. Mrs Mallard is, in this story, no exception.
The tragedy of Mrs Mallard's existence is that it is only when she thinks her husband has been killed that she realizes how little freedom she had when she was with him; although she at first grieves his passing, she also comes to recognize that, without him, she could gain a freedom which has since been lost to her. Unfortunately, and ironically, this is not to be, as Mr Mallard turns out not to be dead at all—at which point shock and disappointment kill his wife.
Chopin describes her protagonist's lack of freedom before the accident by indicating how Mrs Mallard feels when she realizes that freedom is now coming towards her—a "thing" which seemed to "creep . . . out of the sky." Mrs Mallard has known so little freedom that she is at first terrified by it. Then she recognizes that she will no longer have her husband's "powerful will bending hers": his "private" will "imposed" upon her. This suddenly seems to Mrs Mallard a "crime" that she hadn't recognized before, even though she does not think it was always maliciously meant.

In "The Story of an Hour" by Kate Chopin, Mrs. Mallard's sister Josephine tells her that her husband has been killed in a train accident. Although she initially mourns, afterwards as she sits alone Mrs. Mallard begins to reevaluate how she really feels about her husband's death. Awareness awakens within her that she is not really devastated by the disaster, but rather set free.
As she spends the hour in contemplation before she learns that her husband is in fact alive, Mrs. Mallard realizes that before the accident, she was never really free at all. She loved her husband sometimes, but he had "a powerful will bending hers in that blind persistence with which men and women believe they have a right to impose a private will upon a fellow-creature."
It is only in that one hour when she supposes her husband to be dead that Mrs. Mallard is really free. She contemplates and looks forward to "a long procession of years to come" that she would live by herself and during which she could do whatever she wants. She wholeheartedly welcomes and embraces that freedom. She anticipates a long life, whereas before the accident she dreaded a long life.
So we can see that Mrs. Mallard did not consider herself free at all before the accident. Only after the accident when she was sure that her husband was dead did she consider herself completely and truly free.