my fiances...unattractive hygiene..help

Okay so please don't be rude in your responses, I do love this man. And although he is plenty old enough to take care of himself I'm not sure that he was ever taught proper hygiene as a child 
However, he has some serious issues with hygiene that I did not realize until we moved in together. We're getting married in July and this situation need serious help. 
He only showers every few days. Like 2-3. No big deal for some people, he doesn't do manual labor and works in customer service so he doesn't stink but it would be nice if that could happen more often. 
Won't brush his teeth every day. Okay this is probably the worst thing. Because he gets mad if I give him an awkward kiss or make a comment about his breath. I have to ask him every day if he brushed his teeth and if he says no and I tell him to go to do it he says I will later and then doesn't. He seems to think a quick gargle of mouthwash is acceptable replacement for brushing teeth and it actually makes it worse. I feel like I'm mothering a child. It's frustrating. 
The last thing is more of a habit and I've tried everything I can think of and nothing works and it drives me insane. He picks his fingers and toes. Like the hangnails, cuticles and nails. I can't stand the sound and he also gets mad if I say something about it. He's supposedly done it since he was little and I have no hope of stopping it. It just grosses me out because his fingertips are always rough and sometimes bloody from being picked at. 
Please how can I approach these things in a sensitive yet assertive manner????