Kinda a chord/tab mix here for just one guitar, but I think it sounds quite close.
I based this off of the "IS Acoustic Sessions" recordings.
There are only two riffs, and otherwise it's all chords.

Riff 1
e|---------|
B|---------|
G|---------|
D|---------|
A|-0h2-0---|
E|------3--|

Riff 2
e|--------------------|
B|--------------------|
G|----------0---------|
D|------0h2---2p------|
A|---0h3---------3----|
E|-1---------------3--|

Also, for all Fmaj7s, the G string is usually hammered on.



Capo 5

INTRO:

Am G Fmaj7 C
Am G Fmaj7


VERSE:

     Am              G              Fmaj7    C
"I'm looking out the window of this big big, ship"

          Am            G            Fmaj7
"and it's really coming down outside"


PRECHORUS:

Am        G         Fmaj7
     "Somebody once told me"

G                                           (Riff1)  
     "You're gonna know right away"


CHORUS:

Am             G     Fmaj7     C
"She wears a ring already"
          Am     G           Fmaj7 C   
"She's steady in love with another man"


BRIDGE:

          Am G Fmaj7   
"Your hand"


POST-BRIDGE:

Am           G           (Riff2)
"She wears a ring"


ENDING:

Am G Fmaj7 C
Am G Fmaj7