All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and Messenger.
Whatever money you earned is your exclusive right. But the money that you volunteered to spend on yourself, your husband and your children, you have no right to claim compensation from your husband for it. However, if you spent it with the intention of it being returned to you, then you have the right to do so. Please refer to Fatwa 85012.
It should be noted, however, that it is only the customary maintenance costs that should be reimbursed, not the non-customary maintenance costs. Imaam Maalik is quoted in the Mudawwanah as saying: “Compensation may be sought from him without excess.”
Finally, we advise you to reconcile between you and your husband, and the latter should be advised to refrain from divorce and to fear Allaah and not replace what is lawful with what is unlawful. Indeed, Allaah has made marriage lawful and Zina (fornication and adultery) unlawful. Allaah says (what means): {This day [all] good foods have been made lawful, and the food of those who were given the Scripture is lawful for you and your food is lawful for them. And [lawful in marriage are] chaste women from among the believers and chaste women from among those who were given the Scripture before you, when you have given them their due compensation, desiring chastity, not unlawful sexual intercourse or taking [secret] lovers. And whoever denies the faith - his work has become worthless, and he, in the Hereafter, will be among the losers.} [Quran 5:5]
Allaah Knows best.