Breakups and lies and influence

So I have never posted on this before but I thought getting some fresh unbiased opinions would help. So it had been just over 1 month since my boyfriend of 2 years broke up with me. We were best friends for about 4 years before this. In our relationship we were always extremely honest and open. In the last few months he was going through some anxiety and I felt like the dynamic of our relationship was changing. He reassured me multiple times over these past few months that nothing was wrong with us. A couple weeks before he broke up with me we went on a trip that was perfect. When we got back it got weird again and I asked him again if anything was wrong...he said no. That same night he saw his friends and decided to break it off. How does one process this? Any input will help