As said above, it's short for "baby." It has an overly affectionate connotation, though, so unless you're in a romantic relationship with someone or very, very close friends with a certain person, I wouldn't recommend calling them "bhe."
It's generally considered an affectionate /sweet endearment (good, in this context), but for people who are not too interested in endearments, it can be perceived as cheesy.
Also, people usually think nothing of girls calling their close male or female friends "bhe," or of boys calling their very close female friends the same thing, but it is typically considered odd for a guy to do that to a male friend (some may consider it effeminate). It's not considered rude and any guy's free to do it if they wish, but it may end up sending an unintended message.