On the eighth day of the Novena to Saint Teresa of Avila, we ask Christ for the desire for death. By this, we do not mean despair, but a desire to be with Christ in Heaven (which the prayer refers to as the "country of the blessed").
In the first verse of the prayer, the phrase "Thy most constant spouse" refers to the Church, the Bride of Christ.
Prayer for the Eighth Day of the Novena to Saint Teresa of Avila
O most beloved Lord Jesus Christ! we thank Thee for the eminent gift of the desire for death which Thou didst grant to Thy beloved Teresa; we pray Thee, by Thy merits, and by those of Thy most constant spouse, to grant us the grace of desiring death, in order to go and possess Thee eternally in the country of the blessed.
V. St. Teresa, pray for us.
R. That we may become worthy of the promises of Jesus Christ.
Let us pray.
Graciously hear us, O God of our salvation! that as we rejoice in the commemoration of the blessed virgin Teresa, so we may be nourished by her heavenly doctrine, and draw from thence the fervor of a tender devotion; through our Lord Jesus Christ, Thy Son, Who liveth and reigneth with Thee in the unity of the Holy Spirit, God for ever and ever. Amen.