I get the impression that y’all are forgetting that divorce in itself is objectively a mortal sin. Of course, whether or not it would be sinful in a given situation would depend on the reason. Things like abuse, adultery, addictions, or desertion would probably be legitimate reasons, whereas boredom, unhappiness, irreconcilable differences, or growing apart would surely not be legitimate reasons.
In addition, if a couple got divorced for a less-than-legitimate reason, and one of them didn’t want the divorce and did what he or she could to prevent it, then that person wouldn’t be guilty of sin.
Anyway, anyone who has divorced their spouse without a good reason has objectively committed a mortal sin and thus would be barred from Communion until or unless he or she repented through the sacrament of confession AND did what they could to try and repair the marriage.