Is it permissible for the wife to ask to go pray Tarawih behind her ex-husband due to the beauty of his voice, and is this considered a disregard for the husband and an accusation of him being overly strict?

It is better for a woman to pray in her home, as the Prophet (peace be upon him) said: "A woman's prayer in her home is better than her prayer in her courtyard, and her prayer in her inner chamber is better than her prayer in her home." And his saying to Umm Humaid: "Your prayer in your home is better for you than your prayer in your courtyard, and your prayer in your courtyard is better for you than your prayer in your house, and your prayer in your house is better for you than your prayer in the mosque of your people, and your prayer in the mosque of your people is better for you than your prayer in my mosque." The more concealed the place and the further it is from mixing with men, the better it is for her.

A husband should not prevent his wife from going to the mosque if the Sharia conditions are met. Rather, it is recommended for him to permit her, as the Prophet (peace be upon him) said: "Do not prevent the female servants of Allah from the mosques of Allah." This prohibition is for disliking (tanzih) and not for prohibition (tahrim), because the husband's right to his wife's presence in the dwelling is obligatory.

Regarding the wife's request to pray behind her former husband: The default is to have a good opinion of a Muslim, but this request is inappropriate and shows a lack of consideration for the husband's feelings. If the husband prevents his wife from doing so out of jealousy or fear of temptation, there is no blame upon him, because there are many mosques other than that specific one.