While often known for her horror adaptations, Daphne du Maurier has many great shorts, some of which are calming or at least inspiring. The Old Man is one of my favorite pieces by any author.

As someone who had great anxiety problems in the past, what works for me is read the Bible, Psalms helps a lot actually.

While I understand what is your wife's preference, I though that sharing this might help too.

As you probably know, most of the Psalms are short (5 to 30 verses) and some of them also contains short stories about someone that suffers and or is going through a struggle. I believe they're like "mini epics" sometimes.

Get this one for exemple:

Psalms 37:
1 A Psalm of David. Fret not thyself because of evildoers, neither be thou envious against the workers of iniquity.
2 For they shall soon be cut down like the grass, and wither as the green herb.
3 Trust in the LORD, and do good; so shalt thou dwell in the land, and verily thou shalt be fed.
4 Delight thyself also in the LORD; and he shall give thee the desires of thine heart.
5 Commit thy way unto the LORD; trust also in him; and he shall bring it to pass.
6 And he shall bring forth thy righteousness as the light, and thy judgment as the noonday.
7 Rest in the LORD, and wait patiently for him: fret not thyself because of him who prospereth in his way, because of the man who bringeth wicked devices to pass.
8 Cease from anger, and forsake wrath: fret not thyself in any wise to do evil.
9 For evildoers shall be cut off: but those that wait upon the LORD, they shall inherit the earth.
10 For yet a little while, and the wicked shall not be: yea, thou shalt diligently consider his place, and it shall not be.
11 But the meek shall inherit the earth; and shall delight themselves in the abundance of peace.
12 The wicked plotteth against the just, and gnasheth upon him with his teeth.
13 The Lord shall laugh at him: for he seeth that his day is coming.
14 The wicked have drawn out the sword, and have bent their bow, to cast down the poor and needy, and to slay such as be of upright conversation.
15 Their sword shall enter into their own heart, and their bows shall be broken.
16 A little that a righteous man hath is better than the riches of many wicked.
17 For the arms of the wicked shall be broken: but the LORD upholdeth the righteous.
18 The LORD knoweth the days of the upright: and their inheritance shall be for ever.

I'd also suggest reading through some of the earlier stories of the Bible, as they have a reflection value. Like "Someone that got through this and later were able to get out of trouble doing the right things."

As you also talked about your wife's struggle with staying awake alone at night, many Psalms give also confort about this, like:

Psalms 139: 1 To the chief Musician, A Psalm of David. O LORD, thou hast searched me, and known me.
2 Thou knowest my downsitting and mine uprising, thou understandest my thought afar off.
3 Thou compassest my path and my lying down, and art acquainted with all my ways.
4 For there is not a word in my tongue, but, lo, O LORD, thou knowest it altogether.
5 Thou hast beset me behind and before, and laid thine hand upon me.
6 Such knowledge is too wonderful for me; it is high, I cannot attain unto it.
7 Whither shall I go from thy spirit? or whither shall I flee from thy presence?
8 If I ascend up into heaven, thou art there: if I make my bed in hell, behold, thou art there.
9 If I take the wings of the morning, and dwell in the uttermost parts of the sea;
10 Even there shall thy hand lead me, and thy right hand shall hold me.
11 If I say, Surely the darkness shall cover me; even the night shall be light about me.
12 Yea, the darkness hideth not from thee; but the night shineth as the day: the darkness and the light are both alike to thee.
13 For thou hast possessed my reins: thou hast covered me in my mother's womb.

Sorry for the big post, but, as someone who also suffered from something like this, and reading this helped me, personally, I though it may help her too.

And really, im really touched by your love for her. This is really beautifull. Hope more husbands and fathers were like you. You're special. Thanks for your exemple mate!

---Edit

Also, as a musician myself, you may try to play Piano / Acoustic Guitar sounds for her while you read. (There's a lot of these soothing piano and guitar soundtracks in Youtube)
They help one side of the brain to concentrate in the music, while the other concentrate in the voice (in words), giving no room for anxiety to take over, basically.

It's scientifically proven that some sound waves produced by instrumental chords are excelent to calm down brain waves and neural connections, making them "flow" with the calmness of the sound waves. Also helps a lot!

Hope it helps mate! Good luck and much love.

This is a great suggestion. My wife is quite fond of the Psalms, and you are right that there are many stories that might be perfect for my purposes. The story of Ruth springs first to mind. I will keep these in consideration. Maybe I’ll even pull some passages from Ecclesiastes, which, at least in the King James Version, has some of the most beautiful writing in all the Bible.