I actually told my wife, (then girlfriend) about my fetish and what I wanted to do with her long, mid-back length hair when she asked me what my most secret secret was (I had told her that I'd honestly answer any question she asked).

She immediately understood and even offered to let me enjoy her hair at my discretion, with the caveat that, since she'll keep it long and let it grow out for me, I have to be the one to wash it whenever we both have the time to jump in the shower together. Win-win for me!

Now I get to use her hair for hairjobs, tug on it when she's blowing me, cum on it , and wash it off afterwards to get it ready for another round, whenever I want!

So while I understand the trepidation in telling your significant other and being rejected it judged, I also ascribe to the thinking of "No risk, no reward". I was just lucky to have someone willing to give it a chance before denying it.