What's the best action plan of advice for not getting so attached and being more cold-blooded?
I read advice on here and on social media how people say "I hate it when she gets too attached", "I don't wanna be locked down", "I got sides" but to me it's hard to be that emotionally distant with a girl where you truly don't give a fukk if they leave you or not.
It comes with learning to temper your emotions and avoiding being overly caught up beforehand and in also how you place your priorities. You just have to have a strong support system and a set of activities/beliefs you are strongly rooted in. Honestly, no man wants to come in with the mentality of not being overly attached to a woman, but we just have to live according to the realities of today. Just about every man wants that super strong love and to be validated in that belief that your woman will hold you down forever. Reality? She can get bored and leave at any time.
Therefore, you have to mentally have the expectation that she will leave at any time or do something in which you will have to go your separate ways. Then, you have to find several activities that you truly enjoy and have a strong network of friends. For me, it's Jesus, programming, playing games, working out, etc. You simply have to find things that not only keep you occupied, but that you really enjoy doing... activities that you just get lost in doing. Find a set of real cool friends if you don't have them already and go out and do things with them. Build strong bonds with your family. All of this sounds obvious, but it's not put into practice as much as you think because as soon as most dudes get a woman, they can't be found and they start building their world around her.
Realistically, guys don't just have some magic switch where they can shut off their emotions, but it's more along the lines of your emotions adjusting naturally after you've experienced a lot of what goes on in 'modern dating' and you coming to the conclusion that you aren't going to let anyone steal your joy or play with your feelings anymore.
Hmmmm....I'm saying no names and won't elaborate (so don't ask), but be wary of wolves in sheep's clothing who come into this thread pretending to be genuine and then go in other threads and clown the contributors (you know who you are, sweetie). 

to the relationship?..shyt just happened to me earlier tonight with my girl while i was at her place. She was slapping, scratching me up and trying to keep me from leaving, she definitely wasn't playing around at all. I got out of there as quick as i could and i'm not hurt bad of course but now she calling and texting saying she sorry, that she was just a little drunk and shyt but ehh.