Shocking breakup

My bf of 3+ years just ended our relationship suddenly last night. The last month has been lots of excitement for both of us; I got my graduate degree, got a new job, new apartment, new dog. On top of that it was Christmas, his 30th birthday, and his mom&grandma were visiting us for across the country. Everything was good and he was so normal and so happy. He had told my mom he was working on buying me an engagement ring, he made me this beautiful giant hand sketched canvas of the place we had our first date, he had his family meet mine for the first time, and we had plans for me to move with him next year (he is in the military and I have been going to school/working in a different state). Last night I found out that he was texting another woman on a dating app. When I confronted him about it, he lied to my face and then claimed that he had been planning for week on ending it with me after the holidays because of my job being too far away, despite having made solid plans to visit me in February earlier that day. He wouldnt even look at me as I broke down. He drove me to my parents house in the middle of the night and dropped me off without an explanation, an apology, or a goodbye. We had a life planned together. We had plans to get married, have kids, and grow old together. My life has changed in an instant and I am so lost and confused