Search Results: being friends with an ex

So, I have been with my girlfriend for a long time. About 5 1/2 years.

Early in the relationship (around the 3 month mark) she lied to me about her ex texting her. It happened while I think I was looking at her phone whike she wrote a note. I didn't see what it said. She lied and said it was her female roommate that texted her (Completely different names). I gave her about a dozen chances to tell the truth. Finally I told her I already knew and saw. She admitted she got a text from him, but it that she isn't doing anything, he just tries to text her sometimes, and since I had a friend/family member dying of Cancer at the time (R. I. P. Joe Basara), she didn't want me to worry and overthink.

There have been a few more small lies, omissions of truth, and more over the years, but I legitimately believe she loves me. We have been with each other through some of our more difficult times thus far, and she's a very emotionally feeling person. She loves animals, she can't handle people or animals being hurt without bursting into tears, etc.

But I still don't trust her completely. I haven't trusted her since that day when she proved she could lie right to my face. We have been long distance for about 3 years (Her family moved and we weren't equipped to move in together at the time), so I wouldn't even know if anything was going on.

She also lied about the state of her coworker's marriage. She claims she didn't know, but they were in a really bad place and about to divorce. She showed me her texts to make me feel better, and while he definitely talked about the marriage being in a bad spot, there didn't seem to be signs of anything more than him mentioning it and just being an acquaintance. Messages likely weren't deleted.

How can I trust her again? Should I?

2 months ago, I got in contact with a crush I knew in the 7th grade (I'm in the 11th grade rn). She rejected me at that time. We don't stay around each other in person and we don't know where each other lives. But the first month we started talking over instagram, she says she remembers everything about me. More than I remembered about her. We texted, sent voice messages, called each other, laughed at stuff I said, and she tells me that she regrets ignoring me in middle school. Her and I have so much in common and we used to get flirty and talked about nsfw stuff. We're both introverts and we get really shy around the opposite gender. She even called me 'hun' after a compliment. We even talked about how we both got bullied sometimes and I would always push her to not give up on herself. Then she told me about how she only has 2 female friends and like 10 guy friends (including an ex) due to being slut shamed. Then she started getting more quiet. She even ignores my messages while she's deadass online 24/7. I honestly think she talks to other boys and maybe our flame died out.
Recently she ghosted me all last week and still today. Then she casually replies to me messages saying 'good morning' and 'i just need time to myself' and then goes quiet again rn. Not even considering me. I think my love for her is growing too fast.
How can I do this as well? I've gotten advice from my friends and the internet on how to move on from a girl, except im not actually moving on. I'm trying to worry more on myself until she replies to me. I don't know if she's really taking time to herself, talking to other guys, or playing hard to get (which is really unlike her), but I wanna be as thoughtless as her right now to avoid becoming desperate.

How do I learn this emotionless ghosting power?