Another part of the Book of Blessings seems to have an ongoing blessing of wedding rings.
Chapter 1, section III, has:
"III. ORDERS FOR THE BLESSING OF A MARRIED COUPLE
INTRODUCTION
90 A major wedding anniversary, for example, the 25th, 50th or 60th, is a fitting occasion for a special remembrance of the sacrament of marriage by means of the celebration of the proper Mass and prayers provided in the Roman Missal. [footnote 4: See Roman Missal, Ritual Masses: Wedding Mass, 2. The Anniversay of Marriage.]
91 The blessing of a married couple may be celebrated within Mass, by use of the orders of blessing provided in nos. 94-106 and 107-114, or by a blessing outside Mass, celebrated according to the orders given in nos 115-131 and 132-134.
92 A married couple may also request a blessing at a time other than an anniversay for the special needs of their lives or for such occasions as retreats or pilgrimages. If several couples are to be blessed at the same time, the prayer of blessing and the final blessing are adapted accordingly.
93 While maintaining the structure and chief elements of the rite, the minister should adapt the celebration to the circumstances of the place and the married couple and the families involved.
A. ORDER OF BLESSING WITHIN MASS ON THE ANNIVERSARY OF MARRIAGE
…
97 The celebrant may say the following prayer and then incense the couple’s wedding rings.
Lord,
increase and consecrate the love which N. and N.
have for one another.
The wedding rings they once exchanged
are the sign of their fidelity.
May they continue to prosper
in the grace of the sacrament.
We ask this through Christ our Lord.
R. Amen.
98 Or if the couple renews the exchange of rings, the celebrant says the following prayer of blessing.
Lord,
bless and consecrate the love which N. and N.
have for one another.
May these rings be a symbol
of their true faith in each other
and of the grace of the sacrament.
We ask this through Christ our Lord.
R. Amen.
99 One of the following formularies may also be used: (footnote 7: See Rite of Marriage, nos 110-111.)
Lord,
bless these rings which we bless + in your name.
Grant that those who wear them
may always have a deep faith in each other.
May they continue to enjoy your peace and goodwill
and live together in love.
We ask this through Christ our Lord.
R. Amen.
Or:
Lord,
bless + and consecrate the love which N. and N.
have for one another.
May these rings be a symbol
of their true faith in each other
and always remind them of their love.
We ask this through Christ our Lord.
R. Amen. …"
The next ceremony described is “B. ORDER OF BLESSING WITHIN MASS ON OTHER OCCASIONS”. This does not include a blessing of the rings.
But the third ceremony does:
“C. ORDER OF BLESSING OUTSIDE MASS
115 The present order may be used by a priest or deacon. It may also be used by a layperson, who follows the rites and prayers designated for a lay minister. …
124 On a wedding anniversary the minister may say the following prayer and then incense the couple’s wedding rings.”
It then has the same choice of one of the four prayers above, but before the last two it has the rubric “126 A minister who is a priest or a deacon may also use one of the following formularies.”
References:
catholicculture.org/lit/prayers/view.cfm?id=697 has a more complete text of the ceremonies.
Book of Blessings, Liturgical Press, Minnesota, 1989, ISBN 0-8146-1875-8, pages 20-31.