How can a woman treat herself for recurrent sins, especially after noticing that her husband despises her because of her sins, and that she worships Allah in hardship but returns to sins in prosperity, and this time despair has overcome her?

Sins are the cause of calamities, and you did well by attributing your husband's bad temper to your sins. Strive against yourself and seek Allah's help to achieve sincere repentance, for Allah does not disappoint those who seek His help, and whoever strives for His sake, He guides them to His ways. The door of repentance is open until the sun rises from the west, and the one who repents from a sin is like one who has no sin. Seek help in repentance through the company of the righteous, remembrance of Allah (dhikr), and supplication (dua). It is from Allah's mercy that He afflicts you so that you may return to Him.