I messed up, it's my fault my boyfriend and I drifted apart. How do I ask him for a second chance?

That sounds rough. If you don't mind me asking, what did you do?

>>2 It'll sound like hollow excuses, but I've been going through a very stressful time half a year ago and said things I shouldn't have. I wasn't in the mood for intimacy and made it sound as if I wasn't attracted to them anymore. There's also plenty of other stuff I regret saying, e.g. things that might have made them feel like a temporary fling for me. My heart breaks at the thought of not being able to spend my future with them. Around the stressful time we began communicating less and less and after more stupid things I said contact basically ceased. They're a very reclusive person and I fear to have hurt them so much they might never come out of their shell again. I'm giving my best to become a better person so I may be worthy of a second chance. I want to devote myself wholly to them, I love them so, so much, but I fear they might not believe me, think I'm being disingenuous or, if they grant me a second chance, do so out of a sense of being guilt-tripped or something. I don't know how to tell them that after all, I really do genuinely love them so, so much. I love you Nathaniel.

I noticed you did not mentioned a break up and only a drifting apart followed by ceased contact, if that's the case than you should definetly reach out, even if only to end things properly.

As for you messing up, I can't exactly tell how bad it was, honestly perhaps the only person who can tell how bad it was is him. But we cannot change the past, people aren't perfect, if you messed up you messed up, it's better to adress this with him and apologize. Tell him about your feelings, but simply as they are, feelings, be clear about him having the full choice to end things if you're worried about guilty tripping him.

I'm not the best person for advice, but it seems people won't be answearing this posts for quite some days, so here are my 2 cents

Hopefully he's moved on