How Do I Quit Without Making it Personal?

Dear Experts, I'm about to be formally offered a position I really want. I know this from the basic language and tone of my conversations with the hiring manager. I'm just waiting for her to finish speaking with my references and actually put an offer in front of my face. Exciting, yes. Of course I do not plan to quit my current job until I have accepted an offer and have it in writing, but I figured I'd solicit advice sooner so I can prepare. See, my current job is...unique. I am one of five people who work for the company. I work from a home office with just my boss so our relationship over the years has grown from employee-employer to friends. In addition to my professional duties pertaining to the business, he has come to treat me a bit like a personal assistant. I do things like watering plants, helping him pick out an outfit for a dinner, giving advice, depositing personal checks, etc. It's a very relaxed atmosphere, filled with blurred lines and inside jokes. In a way, I'd say he's a bit dependent on me. I'm terrified of quitting. I know it's the right thing for me, but I'm really scared of it blowing up into a big personal thing, when my decision to leave is primarily professional. More important than the friendship, I want to make sure that I can count on him to give me a good recommendation in the future considering this was my first job out of college. How do I handle this the best way? Here is how our CAREEREALISM-Approved Experts answered this question on Twitter:Q#434 Boss could be mad, u can't control it. Hopefully he'll get over it. Helps if ur grateful, lots of notice. (@juliaerickson) Q#434 Set start date so u can give 2-4 weeks notice. Tell boss TY, u grew so much, gr8 opportunity now 4 your career. (@juliaerickson) Q#434 Be direct, upfront and professional. All good things come to an end. If you do it professionally, he'll understand. (@gradversity) Q#434 Start with pos. points of job, thank for opportunity, support of your decision, you have to move on. (@marysevinsky) Q#434 By having an adult conversation. Sit him/her down & submit your resignation. Be honest. You'll get respect. (@blogging4jobs) Q#434 As a biz owner, he should understand. Offer plenty of transition time & help him find replacement. (@jtodonnell) Q#434 Wow! Start w/appreciation for gig and move to how you feel need to grow professionally. Ease out. (@beneubanks) Q#434 Remove the emotion. Hard, but you make decisions on what's best for you long-term. A true friend will understand. (@EmilyBennington) Our Twitter Advice Project (T.A.P.) is no longer an active campaign. To find an answer to the above question, please use the "Search" box in the right-hand column of this website.