If it is a divorce caused by adultery, spousal abuse or refusal to have children the church approves of the divorce, then the innocent person does get to receive communion as I understand it.
I think this is mostly applicable to those who just divorce for any reason and not those allowed by the Church.
That's not really correct. *Anyone* who has divorced and NOT remarried may still receive communion, regardless of the grounds for the divorce. The issue that impedes receiving communion isn't the divorce but the *remarriage.* That constitutes an ongoing state of adultery (Matt. 5:31-32, Matt. 10:09, Mark 10: 11-12, Luke 16:18), or an ongoing state of mortal sin, and THAT is why communion cannot be received.
If the original spouse of each of the "remarried" peple dies, then it is possible for the couple to have their maried sanated in the Church, and from that time on, the marriage will be valid and they can return to the Sacraments. That is the only way for them to do so short of disolving their putative marriage.
Well, actually, there is one additional exception. The Church recognizes that, in some of these second marriages, there are young children involved who are products of that marriage. It may not be financially possible to dissolve the family because of the children's welfare. In this case, IF a couple promises to refrain from relations, and live as "brother and sister," they can approach their pastor with the situation and return to the Sacraments, provided that they can ALSO do this without scandalizing the faithful in their parish.
So if the couple was ever validly married, according to Church requirements, they remain married until one or both dies. Whether the marriage was sacramentally, as opposed to legally, valid, is the question that is raised in annulment proceedings.