Starting to lose hope

My fiance (together 6 years, engaged for 6 months) broke up with me at the start of April. I know we all say it but it was completely out the blue. He had become distant in the few weeks before, so much so that I almost left, only for him to tell me how much he loved me and blamed his behaviour on his head ‘being a mess’. After that, things were really good for a couple weeks. Then he went on a night out and I barely heard from him the next day. It was so out of character that I returned to our home to have it out with him. He said we had been arguing lots recently, which wasn’t true and that I didnt love him enough and that i was unhappy in the relationship, again, not true. I thought there must be more to it and he finally admitted texting someone from work for a few weeks and that he kissed her that day. After this I left the house. We met a couple days later where he then said I had loved him too much and that he didnt think he could love me the right way and needed to be alone. We saw each almost weekly for a month as we sorted out selling our house and I got a lot of mixed messages and he was very touchy and said how much he loved me and missed me. Nearly everytime I’ve seen him he has been a mess, even prompting him to say I’m doing better! He assures me he does not want a relationship with this woman (she is married) and he hasn’t spoken to her since. He said it could have been any girl and he was just chasing a feeling. He said it was a wake up call because he felt we had lost our spark and he found it with her (hard to hear!). He says he will always love me and fancy me but does not want to try and doesn’t think our problems (he hasn’t told me what these our) can be fixed. I told him we should stop seeing each other and talking as much and he was devastated and asked if we could continue to see each other but I said it wouldn’t help. Limited to no contact for over 2 weeks now. I felt like I was in a much better place and when we were talking re house stuff I asked if he would want to meet up this weeknd but he said he would love to but had too much work on. I will see him tomorrow briefly as he is dropping stuff off at the house.
Writing this out it makes me realise there is probably no chance for us.
Despite all the mixed messages I’m thinking he is more than likely leaving me for this other woman, just can’t tell me. I’m doing things for me, I instigated putting the house on the market. I’ve put in a transfer request and booked a holiday. He is still telling me that he is crying at his desk and not happy. Has anyone come back from something this hopeless?