living with a gambling addict

My boyfriend and I recently got an apartment together and have been living together since February. Overall, everything is great. However, he has a gambling problem. In August, he came to me very upset about owing someone $2500, and expressed that gambling was ruining his life, has lost a lot because of it and has prevented him from things he wants like buying a house. We had a very in-depth conversation about how he wanted to stop, and how much grief gambling has caused him. I then, offered to give him a check for the amount under the conditions that he 1. pay me back the full amount by December. 2. NO gambling while he was paying me