Confused

My fiancé broke up with me 3 days ago… we were together for 8 years, through high school and such. I thought everything was going great, we had a few concerns here and there but everything was ok. He started a new medication and he started to change, he smoked weed every day morning to night (has for about a year now) but he started to not make sense and started saying everyone was manipulating him and then he had a newfound spiritual connection to god. He also admitted to me that he lied to me our entire relationship and that he’s had a porn addiction the entire time, that he watched porn every day for 8 years. He asked for a month of space and when he reached out 2 weeks in to start talking again i thought it was great and we could start to work on things. When I went to meet him and talk the first thing he asked of me was to run away with him. I had claimed that the space was doing good for me because I was learning about the things that I could do better to treat him better and he told me he needed me now and I told him I wanted to keep the space a little longer. Which I feel guilty for. He texted me a bunch of texts telling me how he felt rejected and then a lot of angry texts. He’s cut off all his family and most friends, and then he yelled at my autistic younger brother. He called me and I told him he crossed a line and he told me he wouldn’t change and continue to stand up for himself. He then claimed we were at different stages in our life and broke up with me. Later that night I went and got all my stuff, when I couldn’t find something I asked him to let me know when he found it and we’ll find a way to get it back to me. He told me he threw it away and everything else, and then told me he never wanted to speak to me ever again. He completely changed in the last 3 months and he’s never been like this before, he has never said or done anything like this and so I’m so confused and in so much pain.