I duplicated the main photo layer and then applied smart blur and I don’t remember what the radius was for that picture, but it was pretty high. I then used the trusty eraser tool so the blur is only in the background and ta-da!!
Lol sorry if this is not too descriptive, but my Photoshop is in another language and I basically never save PSDs haha. Btw there’s probably an easier way to do that, like using select tool and etc but I don’t have patience for select tools and I’m not one for tutorials and following instructions so I just do what I want :p
Uh but I hope I helped?