Flavio makes an excellent point--though I suppose a relationship between a queen and knight could be fun, if the queen is willing to deal with the Knight's slight immaturity in exchange for his youthful energy.
I also agree that Pentacles in a relationship would certainly indicate stablity with a focus on creature comforts. A couple that wants to have money in the bank, a house, kids, etc. Very soild and down to earth. Hard working, pragmatic--but not above appreciating beauty, art and some of the finer things in life.
Ace/Pents in a relationship would be a stroke of luck, or just that first bit of money fond (a coin on the street) which might bring the two together. A trip to the gym, even, to get started back on the road to Health.
2/Pents is the relationship in that early stage when they're both paying their share for a night out, both getting to know each other physically, both balancing work schedules against going out on dates.
3/Pents is where they work for a common future--I know one couple that opened a furnature store, the husband creating the stuff, the wife buying stock, etc.--this would be the stage where the guy was making pieces for that store, the wife was setting things up...Couples do that; One will work at a job to put the other through medical school, that sort of thing. This is that stage.
Four Pents--as pointed out, this could mean that one of the partners want to hord the money and the other does not. In a good light, it might be that both are hording the money, afraid to spend it, and the relationship might be suffering without them even knowing it because they use any to treat themselves. It may also indicate one partner holding on to the other too tightly. This card raises warning flags--it can indicate a partner who doesn't want the other to go out or have other friends.
5/Pents--ah the dreaded 5/Pents. Financial problems and this will strain the relationship. Hard times. Might also indicate that one of the partners is going through a low physical time and the other partner is feeling that strain.
6/Pents--outside assistance, a gift, a lottery win. In the relationship there is generosity. The sort of relationship where one partner (maybe both) likes spoiling the other with lavish gifts.
7/Pents: This is a time of waiting. Perhaps trying for or waiting for a kid or a new home. The pair want to move on or up--but it's taking time and impatience may strain the relationship.
8/Pents: This could indicate a new start for the pair--a card one might get from a man or woman who has divorsed or been widowed and is starting over again; or a couple who had their home and kids and such--and now the kids are gone and they want to do something different. They're trying their hand at something new, a new line of work, a new home, a new way to relate.
9/Pents: Could indicate a retired couple, or one who is happy living on the comfortable but modest income that they have thanks to the money they made in good times. A physical relationship where the two give each other back rubs, work out in the garden, take nature walks.
10/Pents: A couple who have achieved all they ever worked for--home, family, wealth--enough so that they can spread it wider; create a fund for the college education of grand kids or put a wing on a hospital. A lasting legacy.
Page: Messages are physical--"Action speaks louder than words"--this page would never say, or write when he could DO. He's the boy with a paper route, the kid willing to do chores for extra money that he can put in his piggy bank. He builds his own clubhouse.
Knight: the most serious of the Knights, he's more likely to get a job than go to college--more likely to put himself through college working at a job, come to that. As said, he does want things a certain way--overly organized. In a relationship, could indicate too much of a focus on work or health.
Queen: A woman with taste. Appreciation for beautiful things--with a wisdom for investment and earning money. This is a woman who's not afraid to spend as well as save. Very generous. Knows how to create a beautiful home--and knows how to dress and look conservatively rich herself. Likes the outdoors, excersize and gardening. Traditional.
King: Traditional, conservative, but generous; he has favorite charities and organizations that he gives to regularly. A man of few words, he's likely to give money or gifts to show appreciation. He has worked hard all his life and expects others to do the same; appreciates the rich things in life--but conservative things, elegant thing. He will not try anything radical or new; he doesn't like being embarrassed, and as wealthy as he might be, he hates feeling cheated or that he's been overcharged. He wants home and family to be tasteful, respectable. He dresses well, is on time, neat and organized.
In a relationship, the King could indicate great physical comfort (nice home, money in the bank, etc.) but little flexablity; a life too structured.