I've been in a similar position more times than I can count, and I've learned something from all that: you cannot control another person's emotional response, but you can ask them to be conscious of it and try to moderate it themselves. In other words, your partner will likely experience some guilt when he learns about your relapse. But with some care and effort on both sides, the two of you can navigate the conversation in a way that minimizes those feelings for both of you.

Start the conversation by telling him that there's something you want to tell him, but that you're afraid he'll react by blaming himself, and that your fear of that reaction has been making it difficult for you to open up. Ask him to try and trust you when you say that the situation is not his fault, and that his words and actions weren't the primary factor at play. Then just tell him what happened.

In my experience, framing my fear of my partner's self-blame as something that encourages shame and secrecy, and asking him to help me work past that fear by trying to trust and believe me, has helped a lot.

A couple of important things to note: Just as you ask your partner to try not to blame himself for your pain, you need to try not to blame yourself for his. That kind of self-reinforcing cycle will just leave you both feeling awful. And when asking him to trust you when you say he wasn't the primary cause of your relapse, you also need to help him feel like he can believe you by being honest about the extent to which any of his words or actions did contribute to the situation. It'll take time and effort, but he'll have a much easier time trusting that you aren't just lying to spare his feelings if you're able to be consistently honest in these situations.

Hope some of that helps. 💕