Fixing separated soffit?
It looks like your fascia board behind the gutter has pulled loose. Perhaps when the gutter was attached by the screws drawing the fascia board away because the roofer cut the eave flashing too long. This may be a fix they need to do if the installed the gutter and the eave flashing. 

By the plumb cut I see on the rake board, it appears the fascia used to set back there, until something pulled it out. If the roofers or gutter guys did that, and they may claim they did not, and it is up to you to fix, the gutter needs to be removed, and set the fascia back in its proper location. This may be easier said than done. It can be reset in place with screws preferably about 2 1/2 to 3" long to insure there is good wood to grab to. There should be original nails to go by to place the screws.

After the fascia is set back, then snip the extension of the metal flashing back flush with the fascia, all the gaps should be closed by now and reset the gutter on the now plumb faced, secure fascia board....