Hi.
Bad breath can be caused by any number of things, including smoking, poor oral hygiene, food choices, and certain illnesses. It can usually be treated, but sometimes a person needs to be told that they have bad breath. Many are truly aware that they have stinky breath, but some people have no idea.
I know it can be hard to tell someone something like this--you don't want to embarrass him--but why should he have to wonder why you won't kiss him and why should you miss out on this pleasurable part of being with your boyfriend?
Just level with him and try to deliver the news in the gentlest way possible. Tell him that you really like him and want to be intimate with him in this way, but that his breath bothers you. Let him know that you'd like him to try to do something about it.
If you think it will help, ask him what he thinks the problem might be. This way, you can help him with suggestions.
Of course, there is a chance that he will be offended, but he will probably calm down eventually and may even be glad that you told him.
Good luck.
