I am tired, angry and lost. And I need parental advice.

For those who don’t want to read a rant, here’s the tl;dr: my kid chose to go with my ex and I’m angry and sad and lost. I don’t know what I did wrong and I don’t know how to go about this feeling. I need advise.RANT: I [39M] had raised my kid for the first 15 years. 5 years ago, the mother and I decided to go our separate ways. After 2 years, my kid decided to go with the mother. It has been 3 years now and I still cannot come to terms with that decision.While I respect the decision, I find myself angry. I’m angry I’ve been left alone. I find myself lacking. I cannot understand where I’ve fallen short. I did my best to give the best quality of life. I never failed to show how much I love(d) my kid.I haven’t seen my kid in over 2 years. Every time I reach out, the whole exchange feels “transactional”. I get nonchalant responses. I don’t even get a message unless I send a message first. The only time I do, it’s about something the game set up under my email address. So I have decided to give up as I find this an exercise in futility. I will still be here for the kid, but I am done trying to reach out.For the parents who live separately from their kids, how do you deal with this? Am I wrong to feel this way? Is this normal? Is my kid’s behaviour normal? via /r/Parenting http://bit.ly/2Usmc6p