Should I separate from my husband who used to commit major sins and has repented from them, but is still negligent in prayer and suffers from psychological problems, and will God forgive his past actions?

You must advise your husband who is committing grave sins. If he responds, then praise be to Allah, and be a˹n aid˺ to him in obedience. Allah is Forgiving and Merciful, and He accepts repentance and pardons evil deeds, as mentioned in the verses. However, repentance must be sincere and truthful, and its conditions have been detailed previously.