AITA

I have a best friend we will call him Caleb that I have been friends with for 15 years. Our friendship consisted of going out, messing around, and just being there for each other. Whenever we were single we would hook up and it was a know thing to all his ex’s, our friends, and current partners. He started dating a girl a few years back… we’ll call her Jen. Her and I started getting super close and I considered her a really good friend. At times it got awkward being both of their best friends because they both told me things they didn’t want the other to know. Jen and Caleb were on and off again and more in a situationship than a real relationship. He regularly cheated on her.. I never said anything, they broke up she messed with someone… minded my business. WELL I am coming out of a divorce from a true not great person. They were both always there for me and I appreciated it. Shortly after my divorce started they had a big fight and ended things and both stated they were never getting back together.. I still hung out with both of them .. time passed Jen was hooking up with another dude.. and well Caleb and I messed around. No one said anything… fast forward a few months there in a situationship again… still not saying he’s just a hobosexual…. Well after a lovely night out the next morning a get messages from both of them separately. He said omg I’m so sorry I told her I messed up this is bad and she basically cursing me out followed by blocking me.. now there staying in the situationship and they both blocked me and a few of our mutuals… I know I messed up but it’s not just me right? Do I deserve all the blame? What do i do?