Her husband refuses to let her help him with household expenses
Question

Recently I found a good way to earn experience at working as I don't know what could happen to me if my husband died while I don't have a complete education and I never worked before.
Obviously, I can earn money with that work, which is revising translations. I work at home and I don't have a fixed schedule, I can have work at any time but I can do it while my husband is not present.
My question is: Can my husband control the way I spend my money? He doesn't let me buy anything for the house with my own money, he doesn't even let me buy something I want to buy, he says he can buy it for me another time and he doesn't like me to spend any of my money, although it could make things easier for him and for me. I'm living with my parents-in-law for more than a year now and we are joining money to rent a house soon, in sha Allah. But he doesn't let me help him to join money to buy the things for the house like fridge, washing machine, etc.
I know it's his responsibility to take care of these things, but can't I help? What am I supposed to do with the money I may earn except giving in charity? I could do a lot of things and take a lot of weight from my husband's shoulders if I helped him with my income.
Is it permissible if I put some of my money with the savings we have without his knowledge as sadaqah?
Please advise me.
Praise be to Allah.We congratulate you for having this virtuous husband who is a man of good character and high integrity. There are very few men like him who refrain from taking their wives’ wealth and insist on keeping away from it and not touching it so that they will not undermine their wives’ rights or fall into dubious matters.  This is part of the kind and honourable treatment that Allah enjoins, as He says (interpretation of the meaning):
“And live with them honourably”
[al-Nisa 4:19]. 
It was narrated from Hakeem ibn Mu‘awiyah al-Qushayri that his father said:
I said: O Messenger of Allah, what are the rights of the wife of one of us over him? He said, “That you feed her when you feed yourself and clothe her when you clothe yourself or when you earn some income, that you do not hit her in the face, you do not say ‘May Allah make your face ugly’ and you do not forsake her, except in the house.” 
Narrated by Abu Dawood in al-Sunan, 2142 
Ash-Shaykh Ibn ‘Uthaymeen (may Allah have mercy on him) said: 
What this means is: do not buy clothes or food only for yourself and not for her; rather she is your partner and you have to spend on her as you spend on yourself.
End quote from Sharh Riyadh al-Saliheen, 3/131. 
Your husband is obeying the command of the Messenger of Allah (blessings and peace of Allah be upon him) by spending fully on your maintenance; in fact he is going over and above that by spending on extras from his own money and refusing any financial help on your part. 
Hence we advise you to respond to this kindness with kindness and do not give up trying to help financially, even if that is by depositing some of your money in his account without him realising, because it is not essential for him to know about that. Or you could buy things that your husband needs or that the house needs before he realises it, or buy him a valuable gift, especially something that is important to him, or keep the money to give to him at the time of need, and other kinds of beneficial spending. 
Then whatever is left over of your money, after you have helped him in whatever way you can and put whatever you can give in your joint account and given in charity, you can save it in your own personal account, because perhaps you will need it for both of you, or your children may benefit from it. 
And Allah knows best.