How can I help my SO quit smoking?

My boyfriend has been smoking for the last 9 years of his life. He has been trying really hard to quit but has recently slipped up and he also lied to me about it for 2 days until I found out on my own. This definitely angered me and he was apologetic and agreed to go back on the nic patch but he’s super irritable again and angry. When he calls me to talk about it and I try to encourage him and say I’m proud of him and I love him and I’m here to support him, it doesn’t seem to help and he just texted me after one of these phone calls and said “I feel like I’m fighting this alone” and yesterday he said he felt like I didn’t care. I know it’s probably just the irritability but this hurts my feelings and I just don’t know how else I can help. Any advice welcomed thank you!!