Partner got the most horrendous haircut...

My partner got this haircut yesterday and I'm pissed off at him because he's always had nice hair before and he asked me what hair styles I like before he got it done and was hinting towards the one he got, so I told him, before he got it done, that I hate that style and I think it makes people look stupid and ugly. Nevertheless I came home from work and I was horrifies to find he had ignored me and got it done. I was speechless. All I could say was how it made him look old, and his forehead looked huge and like he was going bald. Anyone who knows me knows I will be bluntly honest about things, I don't say it to be a dick, I say it to tell the truth. It just looked absolutely horrendous, like I cannot describe, I really could cry to be honest.The one thing I did not say though is the thing that distresses me the most. In ten years together I have never, ever found him to be unattractive, I always found him to be extremely attractive. But I walked in and saw this last night and the first thing I thought really upset me. I actually thought "he looks ugly!" It sounds like I'm being awful but I can barely look at him now with this stupid hair he's gone and got and its really distressing me and I don't know what to do because I'm going to have to tell him at some point but how?