I agree that you need to stop giving her money. But also agree that you need to be firm with your partner. If you have a shared bank account you might want to get your own so you can control your own money. This may (probably will) cause friction with your partner. If it is in a shared account then he could just take it out and give it to her without your approval. If you don't think you can talk it out on your own with him, getting couples therapy to discuss the money issues might help. Money is a hard topic to discuss.