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.
May Allaah reward you for the help you are giving your husband in spending on the household. This indicates your generous character and is seen as an act of kindness and assistance, since spending on wife and children is a duty upon the husband, and the wife is exempt from all such expenses. Further, it is wrong for the husband to force his wife in this regard. For more details, please refer to Fataawa 86646 and 85012.
If your husband makes your request to save some of your salary a cause of dispute, then he is in error. It is best to continue speaking with him in a kind way. If he responds positively to that, then so be it; otherwise, have patience and persevere. If you need to ask for the intervention of persons who are close to him, then do so.
Finally, you should know that going out to work is not required of the wife, but it is more preferred that she remains at home and takes care of her children; Allaah The Exalted said (what means): {And abide in your houses and do not display yourselves as [was] the display of the former times of ignorance. And establish prayer and give Zakah and obey Allaah and His Messenger. Allaah intends only to remove from you the impurity [of sin], O people of the [Prophet's] household, and to purify you with [extensive] purification.} [Quran 33:33].
Allaah Knows best.