This is not praying to the Lord FOR a husband/wife, because you should have settled that already – that the Lord is going to provide. Amen.
Pray for your future husband/wife-to-be, remember they actually exist! They are alive somewhere out there and looking and praying for you too.
Pray for their faith, health, strength, family, career, cover them with the Blood of Jesus, bind any hindrances in their life etc.
You should get used to praying from him/her now because when you are married you will be praying for eachother everyday so go on… get started.
Therefore we also pray always for you that our God would count you worthy of this calling, and fulfill all the good pleasure of His goodness and the work of faith with power 2 Thessalonians 1:11 (NKJV)