<human>: It's been a year and a half since my ex of 3 years ended our on/off relationship. She broke up with me after 6 months, came back, then stayed for another 2+ years and left again. Both times she left to pursue someone else. Most recently she dumped me to date her friend's brother. (who dumped her after a month)

She's had many boyfriends after him (at least 3), but to this point none have lasted as long as me. She's asked me to be friends many times but I am not interested. I still kind of want her back but I may just be lonely because I haven't had a girlfriend since her. 

Today is her birthday, and I don't know if I should just wish her a happy birthday. I don't want to seem bitter. The last time she pushed me to be friends, I told her if we're both doing okay, we should just continue not talking. I think I am moving on. I have a lot of other things I'm focusing on like getting a job. It still kind of feels empty though because I miss her.

Give me the gist of the text in a nutshell
<bot>: was broken up with a year and a half ago for her friend's brother. That didn't last, she's dated a lot of guys after me. Today is my ex's birthday. Should I wish her a happy birthday?