The answer to your question really depends on what you mean when you say that a spouse is not “doing the will of God.”  Do you mean that he or she is not behaving toward you in the marriage in the way that you understand Biblical counsel about marriage?  Do you mean that the spouse is not doing the things that you think characterize a person who IS doing the will of God?  Do you mean that the spouse is living a “worldly” life, that is, making decisions on the same basis as those who are not Christians?  Or do you mean that the spouse is leading a life of unrighteousness, that is, doing things that are clearly against Biblical teachings, perhaps things that are even against the laws of society?

The end of your question refers to that spouse as “the one who is not doing what they should.”  That could be very different from the concept of “doing the will of God,” because everyone’s perspective on what others “should” do is different.  Nevertheless, here is one possible answer.

Doing the will of God can be a challenge for any of us and we certainly can influence our spouses either for or against doing the will of God.  Adam and Eve found this out the hard way (Gen. 3:6-7).  God tells Adam in Gen 2:17 that he could eat of every tree in the Garden except for one.  We assume that Adam passed this information on to Eve when she was created; however, when Satan tricked her and told her that she would not surely die, she ate.  Adam still knew what the rules were but he didn’t want to lose his companion, so he ate as well.  Sin entered into the world and continues to this day.  (There will be a day when sin is no longer in the world and mankind will be able to do the will of God (Rev. 20:10)

How do we know what the “will of God” is?  John 6:35-47 tells us that we are to believe in Jesus.  We are to follow the teachings of the scriptures.  Matt 7 is a wonderful chapter telling us how to act toward others and how to build a foundation of doing God’s will.  Verse 11 tells us that our Father will give us good gifts if we obey Him. 

Blessings are gifts from God.  They can be things like getting a job, being sheltered from some tragedy, or learning some valuable lesson.  They can be spiritual things like being able to understand a Bible passage more clearly.  Blessings can come to us individually or as a group.  You might be blessed individually by not being killed in a car accident or you might be blessed as a group of students studying a particular book of the Bible and really understanding it. 

A gift is something that someone gives to another for some reason.    If we are expecting to get something (a gift or reward) from someone because of something we have done, then our heart is not in the correct attitude.  We are not to try to act a certain way just because we want blessings or gifts from God.  We are to do it willingly because we want to serve God to the best of our ability.  Matt. 5:1-12 gives us a good list as to the type of behavior and personality that the Lord is looking for.  The people with those behaviors or personality will receive blessings or gifts from God because of some action that they took.  Col. 3:23tells us that we are to do our work heartily or from the heart as for the Lord, rather than for men.

We CANNOT MAKE another person act a certain way.  Ask any parent that wanted their kid to do one thing and the kid did just the opposite.  As parents, spouses, friends, teachers, we can try to guide another into a certain path, but we cannot make them take that path.  Sometimes it takes a while and/or some harsh experiences before a person starts to see the wisdom of what another was saying.  just like you can’t make a boat turn around abruptly, sometimes people need time and gentle coaxing, and observing blessings coming to others before they decide to take that path themselves.