Deciphering the mind of a man.

Can someone explain men to me and their fear of relationships. I honestly never post on here but i need opinions so bare with me:

I started seeing this guy (let’s call him mark) about 4 years ago at college and after a few months he decided to return to his ex girlfriend who lived a few states away. I perused another guy for 3 years and we broke up. Well me and Mark ran into each other at a bar and became friends. His friends knew he liked me and wanted to date me but i kept my guard up from what happened year before. We graduated and i moved to The Bay Area. About three months after graduation he moved to SF for a job and wanted to start hanging. Old feelings rekindled between both of us. We were perfect for each other, never arguing, pushing each other to be the best, making future plans, and he loved to tell me his crazy ideas for programming since he knew i loved listening. We went on a bunch of dates for the next few months. We hung out one night and went out for drinks and breakfast the next morning and i took the train home. We spoke for a few days after and then he disappeared for a month. I reached out a bunch and he once apologized for ghosting on me then disappeared again which resulted in me getting fed up and texted him where he finally responded:

Tbh what does any of this truly mean? He even agreed in the past we are perfect together and everyone saw it. Why are guys so chicken to commit?