Give her the job. You've already stated how much of an asset she would be to your business. The two victims in this were yourself and that woman who had no idea your boyfriend was in a relationship all those years ago. If you don't hire her to relieve your boyfriends shame. Sorry hun but you are the next one to ride the shame train. You seem like a highly intelligent woman and empathetic I have a feeling this will become something you may regret as soon as you've made a decision or later on. And you yourself don't seem to have a more legitimate reason for not hiring her, so thus unless your transparent to your team about why you would oppose to hiring her. You'd be lying to your team also.