Pretty sure lunar effect is a real, scientifically confirmed thing, just known by a different name. Perhaps not the full moon specifically, but we do oscillate according to the moon phase. It’s called circalunar cycles. The name might sound familiar to circadian cycles because they both derive from the same word structure, ie circa-dia (“around a day”) and circa-lunar (“around a month”)
At minimum, I’m quite surprised that Wikipedia lists this as a pseudoscience, because my impression has generally been that circadian researchers acknowledge circalunar cycles as a given
Change isn’t necessarily impossible, but it’s really difficult and requires a huge amount of self discipline - if someone changes, they will be a standout exception rather then the norm. I urge you to consider that someone who ghosts you likely does not value you enough to be willing or able to put in the effort to change. Ghosting is deeply rude to do to anyone, and especially toward your significant other.
Take my interpretation with a mountain of salt, because I don’t know the full story. But, from what you said, it seems more likely that he reached out to you because you were a convenient backup