Boyfriend cheated

My boyfriend cheated on me after being with me for a month and I wanna write a letter to her:

Just because you don’t have the confidence to be with someone like me doesn’t mean you've made the right decision. I know you liked me and that’s why we spent the night together, and that doesn’t mean you’re obligated to be my boyfriend, however after seeing you with that girl yesterday it made me question your judgement and taste in women, and I am thoroughly disappointed because you should know you’re worth more than that (she didn’t even try to stand up for you when I started using foul language, which I’m very sorry for, but I couldn’t help myself because it was like a knife in my heart) therefore I’ve come to the conclusion that you’re a very sad insecure man who’s probably been thru too many bad relationships and heartbreaks. At this point I’ve got nothing else to say but good bye and good luck on finding your better half in life. I really did love you John but your dishonesty and deceitfulness have made it hard to trust you anymore.