Is common-law marriage considered valid, from a Shar'i perspective, if the man is already married? And does the common-law wife deserve the same rights as the official wife, in terms of financial support and clothing? And is she entitled to seek a divorce due to the husband's failure to deal justly between his two wives?

The questioner must repent to Allah for interacting with a non-mahram man and speaking to him unlawfully. If the conditions for marriage mentioned in Fatwa no. 32719 are met, then the marriage is valid, and the husband must be just between his two wives in terms of spending and clothing. If the husband is not just, the wife may request a divorce or remain and waive some of her rights. If the conditions for the validity of the marriage, such as witnesses or a guardian, are not met, then the marriage is invalid and must be annulled.