I confess that (not atypically) my interest in St. Rita is mostly selfish. She is, among other things, the patroness of difficult marriages and although my marriage is not difficult, I've always thought that in the larger sense "difficult marriage" is redundant given that we tend to marry our opposites and that provides plenty of opportunities for cross-carrying. Since St. Rita's feast day coincides with our wedding anniversary, I was particularly warm to St. Rita.
But now I find that the patroness of difficult marriages title turns out to have been acquired under false pretences. Alas and alack! (Though perhaps, saintly as she is and thus able to sympathize even when she has no direct experience of that which she sympathizes, she'll accept the title despite the misunderstanding that has cropped up.)
That misunderstanding I found explained here, a pdf from the National Shrine of St. Rita. It was said that she had a violent husband, but it appears she did not:
The above few lines which express the sentiments of an author whose identity remains unknown, were not written for any book, but were painted, rather, on what has come to be called the ‘monumental coffin’ of Saint Rita, - the coffin in which her body was reverently placed in 1462, five years after her death...
The words of the hymn are at one and the same time a testament to Rita’s great virtue and, as we have to believe, the source of legitimate disappointment for her up until recent times. The story of her virtue is well known; that of her disappointment is perhaps less clear. It was the misreading of this hymn, written in the 15th-century dialect of Cascia, that gave rise to the unfortunate tradition of Rita’s ‘violent’ spouse. In 1626, during the beatification process, the judges reported that the coffin was greatly damaged. Undoubtedly, it was also severly darkened by over a century of smoke from the votive candles which devotees had brought to be burned in Rita’s honor.The difficult to decipher lettering was thought to have revealed a ‘maritu feroce’ or ‘violent husband’ and so the sad tradition was born. Only in 1925 was the coffin restored and cleaned and with it the ‘maritu’ [husband] was more properly seen to be ‘tantu’ [very], indicating the severity of Rita’s forehead wound.