A technical comment or two that does not touch upon the OP (which I do not want to address).
A given marriage can be invalid due to one or more causes. The causes can be grouped under three headings: consent, impediments, and form. If a person’s marital consent is not, in fact, marital, then there is no marriage (e.g., a young woman is forced into marriage by her parents). If a person is impeded from contracting marriage, the act of consent can be sufficient and yet there will be no marriage (e.g., a man tries to marry his own sister). Finally, a person can have proper consent and not be impeded but might express consent in an inadequate manner (e.g., a Catholic does not marry “in the Church”). Somebody could appear to marry but the marriage would be invalid due to causes in each heading (such as, a Catholic attempts marriage before a civil judge, with a divorced woman, and he excludes the very notion of having children with her).
An impediment is a fact that, according to the law, makes a person unable to marry in all or particular circumstances. There is no legal impediment concerning lying/infidelity. A person’s marital consent can be eliminated because of deceit or an exclusion of the good of fidelity but these are issues of consent, not legal capacity.
Dan