What is the ruling regarding a wife remaining with her husband who does not pray and sometimes utters words of disbelief, and should she dissolve her marriage to him while she is pregnant?

If a husband utters words of disbelief (kufr), he is in grave danger and may fall into apostasy (riddah), which scholars have defined as "the disbelief of a Muslim through an explicit statement, a word that necessitates it, or an action that implies it." Whoever voluntarily insults Allah or His Messenger, or mocks them, is a disbeliever both inwardly and outwardly. He must be advised; if he repents, then all is well and good. Otherwise, it is not permissible for you to allow him access to yourself, and you must separate from him.

Not all anger prevents accountability unless it reaches a degree where one loses consciousness. As for abandoning prayer, it is a grave sin and one of the major sins. Some scholars have gone so far as to consider one who abandons it a disbeliever, though the majority hold that he does not become a disbeliever by doing so.

Supplication (du'a) is the weapon of the believer for fulfilling needs and alleviating distress. Therefore, you must turn to Allah and supplicate for your husband's repentance and guidance.