How does one adopt an abundance mentality without the abundance? I am struggling greatly with this. Whenever I just try to fake it, I usually get called on my bluff and end up alone.

Edit: adding an example

last gf was flaking out on me when we were supposed to meet up. She wasn't cheating or anything, just inconsiderate. I let her know that we couldn't be in a relationship if she was going to flake out on me all the time. She was really apologetic at first and then broke up with me two weeks later.