Can a divorced man join the Catholic Church and marry a Catholic woman?
A divorced man who is not in a relationship with anyone else may
join the Catholic Church. He may not marry until he receives a
declaration of nullity(which means the marriage was invalid from
the very beginning for some reason). If it is found by the tribunal
that nullity has not been proven you may not marry as your marriage
to the one you civilly divorced is valid. Marriage holds the
presumption of the law. It must be proven otherwise. If you or the
person you civilly divorced aren't baptized then you might be able
to have the marriage dissolved by the Pope using the Petrine
Privilege. Talk to your diocesan chancery for more details.