Is it okay for my boyfriend and I to live together in order to save money?
No. Ask yourself this question: Do you really think that your need to save money is beyond God's scope of understanding? When He wrote His Word and set His precepts as our standards, do you think that He didn't know how life would be for you? None of us are exempt from God's moral standards.
Many reasons can be pointed out as to why living with your boyfriend is a bad idea. First of all, it cheapens your wedding day. Secondly, studies show that couple's whom live together before marriage are far more likely to divorce than those who do not. Finally, and most important, living together before marriage directly opposes against God"s plan for the marriage covenant. "Marriage should be honored by all, and the marriage bed kept pure, for God will judge the adulterer and all the sexually immoral" (Hebrews 13:4).
"And walk in love, as Christ also hath loved us, and hath given himself for us an offering and a sacrifice to God for a sweet smelling savour. But fornication, and all uncleanness, or covetousness, let it not be once named among you, as becometh saints; Neither filthiness, nor foolish talking, nor jesting, which are not convenient: but rather giving of thanks" (Ephesians 5:2-4).
Note what the apostle Paul said in the previous Scripture regarding to sexual immorality. When a couple comes together outside of marriage, it is considered immoral in God's eyes. For this reason, the apostle Paul admonishes the reader to live in such a manner that is pleasing to God. Therefore, "there must not be even a hint of sexual immorality" amongst those who have Jesus in their hearts.
If you are living together already, pray that the Lord will give you the strength to do what is right no matter the consequences. You need to remove yourself from your current situation. Consider seeking good Christian counseling for yourself and your boyfriend. Together, ask the Lord for forgiveness and repent. Pray that the Lord will restore your relationship in His eyes so that you can come together in purity on your wedding day. God can turn your past transgressions into a beautiful marriage union in which He will bless your relationship.