<human>: He (who I'll refer to as Peter) and I have been together for 14 months. We have (had?) a wonderful relationship, and my daughter gets along with him well. 

Before we got together, Peter explained to me that he was an ex Ketamine addict, with a couple of minor relapses, and that this addiction had been so bad that it had cost him his bladder. As he was something special, I let it go and said that I could deal with addiction but not lies.

Fast forward to 10 months in. Something is off. You know how sometimes, you just...know? I tried to calmly call him on it a couple of times and it got me nowhere. Eventually at his birthday party (mid September), surrounded by friends of his using K, I caught him. He admitted to using it several times over the past couple of months. We nearly broke up. 

Long story short I gave him a second chance. I made him get treatment for the depression that he said caused the relapse, encouraged him into joining a Narcotics Anonymous group and addressed the issues with myself/our relationship that he said weren't helping. It's been hard, and he has been quite defensive at times.

I suspect that he continues to use, but I don't have any proof. Talking to him gets a denial. Am I just being paranoid? I don't want to throw what we have away. Please give me some advice.

Can you condense the text into three sentences or less?
<bot>: I suspect that my SO, whom I adore, continues to abuse Ketamine behind my back. Seeking advice on how to proceed.