Should I let my ex back into my life?

Janae • Enjoying every moment❤️
So I'm going to start from the very beginning and make this post as short as I possibly can.... So me and my ex were together from sophomore year to junior year and almost made it to a year, but he ended our relationship before then. It was completely unexpected because our relationship was perfect and we barely argued. This crushed me because he was my first love. So, in an attempt to understand what had happened I convinced him to go out to dinner with me so we could talk it over. To summarize that talk, he told me that he didn't want me with other guys but had lost feelings for me. This just added another blow to it. How do you just fall out of love like that? So a week after that I find out he is with another girl so I decided to be with another guy. Since October of last school year i hadn't talked to him.
So fast forward to this year. Me and the guy i was with after him broke up on a bitter note this past June and the beginning of February (this month) my ex started texting me again. At first it was friendly, but he soon told me he still loved me. He told me he wanted a future with me and that he had only broken up with me because he was going through a lot at that time and was too embarrassed and ashamed to let me know about it. He also told me that the girl he had been with was only play at first until he found out i was with a guy, that's when he made it serious with her.... (Side note: he broke up with his girlfriend of 7 months earlier this month to be with me and also because their relationship wasn't going anywhere and he realized he really wanted to be with me.) 
I know this is long but I want to provide you guys with a lot of information and not leave anything out. So to end it, we are both seniors in high school, and he says he wants to be with me for the rest of his life. However, he says he wants to take it slow so we are not together at this point. Considering all that has happened, should I let him back into my life as my partner? (If anyone needs further information don't hesitate to ask.)