Tithing is a commendable goal and is a worthy standard for our giving–and no, it isn't just for rich people. On one occasion, Jesus commended a poor widow because "she, out of her poverty, put in everything–all she had to live on" (Mark 12:44). She did it out of her love for God.
In the Old Testament, tithing was an important part of the worship of God's people, and God promised to bless them if they obeyed His command to tithe. The Bible says, "Bring the whole tithe into the storehouse ... and see if I will not throw open the floodgates of heaven and pour out so much blessing that you will not have room enough for it" (Malachi 3:10). Think how much greater our impact on the world would be if every Christian followed this injunction.
Someone has said that our giving is the true measure of our commitment to Christ–and it's true. Which should be more important: your wallet, or God's work? But which actually is more important to you and your husband? Put Christ first in your life, and then ask Him to help you use the resources He has given you for His service.
The Bible says, "Each man should give what he has decided in his heart to give, not reluctantly or under compulsion, for God loves a cheerful giver" (2 Corinthians 9:7). The more we love Christ, the more we will want to advance His work by our giving.