I know it probably sounds really lame, but I’ve always found the best way is to talk to them about it. It really sucks when you have to do something like that, but I’ve found it’s better that way than to let it drag on on until you explode. If he’s a really good guy, he should totally understand and give you some space. Probably hasn’t helped you much, but just letting you know what I’d do if it was me.
