Unbearingly is sometimes labelled simply as being an incorrect word, and that the correct word for it is "unbearably." However, in slang, these two words
mean different things. Unbearingly means to not be able to stand
something to the extent that it is "breaking your back," or troubling you severely, and so you want it to go away (or desire to get away from it).
Here is an example of the difference between "unbearably" (which is a
real word) and unbearingly (which is slang and not accepted in formal writing):
"That
person was unbearingly nice" means that they were so nice it was unpleasant, perhaps
annoying, or in some fashion distasteful. You didn't like it and were happy to get away from them. However, "That
person was unbearably nice" means the opposite: the person was so nice, you could not resist them; you couldn'
t resist falling for their charms, essentially, and will likely look forward to seeing them again.
Of course, slang and "incorrect" terms differ by region, and in some places these two might mean the same thing, but where I live they do not.