My Answer to city girl
Well, city girl and I have gotten quite a bit of help with this difficult question.
There might not be enough information for me to give a completely accurate response. For instance, did this woman lead her husband to believe she was chaste until her marriage? In other words, was there a deception there previously, and that's what is really bothering her? If so, she would need to receive forgiveness for that from Our Lord, as well as good spiritual advice on how to handle it.
Or did her husband know she had other intimate relationships, just not all the details. In this case, giving him details would be selfish, as she would be seeking to relieve her suffering by increasing his.
Either way, if she is struggling with her past, it is possible that she is having more of a sense of repentance now than she did originally (very typical as one ages and matures, the nature of our past transgressions become more clear to us). Doing a general confession, or a confession where a life review of the past, even forgiven, sins are reviewed, will offer her a chance to heal even more deeply and make some spiritual connections between past and current sins.
The issue of this woman being afraid her husband will leave her is troubling. This could just be hyperbole, similar to when a teen is in trouble and says, "My parents are going to kill me."
Or, there could be a real lack of intimacy and trust in that marriage, partly due to either spouses past relationships. Either way, healing must take place to strengthen the marriage and the partners as individuals. Unfortunately, her husband can not heal her. Only Christ can. What she needs to do use all the tools we have been given for spiritual healing: prayer, fasting, and alms giving.
Prayer can include attending Mass or Liturgy more regularly, receiving Our Lord in Holy Communion as often as possible, going to confession on a regular basis for current transgressions, and keeping on top of the present moment, instead of turning the gaze backward. As with any human, this woman is currently sinning every day, and a distraction regarding the past can obscure that reality, and cause even more spiritual sickness.
Fasting can help with healing from bodily transgressions by putting the material and spiritual realm into the proper priority. A simple fast is Wednesday and Friday refraining from consuming meat, or another favorite food that is regularly enjoyed. The point is not to diminish physical health, but to deny the senses and heighten the spiritual consciousness.
In her case, alms giving could simply be volunteering her time and talents at a homeless shelter, a crisis pregnancy center, or teaching young people their faith. In other words, she could help repair the injury to Our Lord by strengthening His mystical body here on earth.
It would seem as if all should be an open book in marriage, if in fact, the two spouses are one flesh. However, in reality, we are fallen, flawed people, and out of respect and charity to the other spouse, some things are better off left unsaid. By "confessing" to her husband, she could unwittingly open a Pandora's box of suspicion,
insecurity and shame, and the marriage would be further damaged.
So, practically speaking, I would strongly discourage her from telling her husband anything without a long term span of spiritual preparation including the items outlined above: Sacramental grace, prayer, fasting, alms giving and spiritual direction.
Also, I would encourage her to be as loving a wife as she can be, both in her daily duties, and in her physical relationship with her husband. Love does heal, and if she allows herself to shower her family with her loving care, and allows herself to unreservedly love, and be loved by, her husband, she may find that authentic love heals the hurts of past counterfeit experiences.
City girl also mentioned on a personal note she has a boyfriend and has things she doesn't want him to know. To really answer that, I need to know some things like, how long have you dated, is this a potential spouse, are these past things forgiven sins, or simply experiences that are private. In any relationship, there is a degree of privacy that must be respected, and a balance must be reached between privacy and intimacy. By and large, my advice would be the same as above.
So, there you go. I did my best, but am certainly open for further input. City and girl her friend will certainly be in my prayers!