A Christian in the Renaissance might argue that in order to truly love another person, who must first and foremost love the creator of that person: God. Only a prior love of God (such a Christian might argue) will show us how to love all of God's creatures in the proper way. By this standard, neither Macbeth nor his Lady truly love one another, as the history of their relationship shows.
To begin, I think that this question should be moved to the Discussion section (you will receive many more great points-of-view there).
As for myself, given this question calls for a subjective answer, I think that Macbeth did, in fact, love his wife. Lady Macbeth, on the other hand, I think was more in love with the idea of Macbeth being king than being her husband.
Lady Macbeth was constantly belittling her husband. Readers, or watchers, first come to know her as she is reading the letter from Macbeth. After she finds out about the prophecies, Lady Macbeth questions his ability to do what needs to be done to gain the crown:
Yet do I fear thy nature;
It is too full o' the milk of human kindness
To catch the nearest way.
Here, she is questioning if he is man enough to take the crown (as she wishes him to do).
Macbeth, on the other hand, does love his wife. While it is not until his "Tomorrow, tomorrow, tomorrow" speech that readers come to see this, it is apparent from the way he insures that her wishes are met. In the end, his actions have led to her death and he feels sorry for what he has done (depending upon what school of interpretation one adheres to regarding the soliloquy).