Thank you for reaching out to us. We appreciate the sensitive nature of this question.
You are fully permitted to immerse in a mikveh for
spiritual purposes, and prior to your re-marriage would be a fitting time to do so.
Throughout your married life, you may immerse in the mikveh if you so desire. However, you are not halachically obligated to immerse and you and your husband are not required to observe any of the laws of
niddah. Your status is similar to that of a woman who has undergone a hysterectomy or menopause. Such a woman continues to have a fulfilling and holy marriage without the observance of mikveh.