Broken trust

My fiance has a history with substance abuse and has, at least to my knowledge, been in recovery. I went on vacation because I believed that he was in recovery and his assurance that there would be no issues. When I returned I had asked him if there were any slip ups and he said no. Then a couple of nights later a friend of ours called me to tell me that she was told he had overdosed while I was gone and it was a bad one. I confronted him immediately and he denied it. Later on that night I was approached by my sister and she informed me that it was her who found him overdosed and not breathing in our vehicle in front of his friend's house. She and a couple of other people helped revive him. It took 6 nasal narcans and an injection of narcan before he was revived. I confronted him again and he tried to deny it again but finally admitted it after I mentioned my sister, but told me he had no plans of telling me. This was after he reassured me I would never have to worry about him overdosing again. This was #6 since February of 2024.

I'm struggling so badly to trust him at all let alone when it involves this substance or his friends that still use it. I've only known for two days now and he is expecting me to just trust him completely again with not repercussions.