Despite what some people think, being a stay at home mom is a lot of work. Children to care for, a house to somehow keep clean, maybe even a work at home job or home business. It's not as easy as it may appear on the surface. Being a stay at home mom can also sometimes be a strain on a marriage.
There are reasons for this, such as money. But resentments can build if not brought into the light. One common resentment is simply that one partner doesn't have to work outside the home. It is very easy for a husband to get frustrated that his wife gets all day with the kids and he has to work all the time. At the same time, the stay at home wife may get frustrated that she never gets a break from the kids. Obviously such issues should be discussed.
One of the ways to ease the problem is to make sure that each partner gets reasonable breaks, both as a couple and individually. The husband needs to realize that watching his own children as his wife gets a break out of the house is not babysitting. The wife needs to realize that sometimes her husband needs to do more than go to work and go home. This also means take date nights. This can be difficult when money is tight, but do try to find a way. You may be able to trade babysitting or get the grandparents to do it, then do something cheap together.
The point is that you still need to have fun as a couple. Money resentments build as finances get tighter due to living on a single income. For most families this is not an easy thing to do. It's not fun having to make do, do without, skip vacations and so forth because the budget won't allow it.
Sometimes financial problems are bad enough that a reassessment is necessary. Maybe it's time to reconsider your current setup. Maybe being a 100% stay at home mom isn't working. A night job could be in order so as to avoid daycare issues, or finding a way to earn from home. But you can't let financial stressors get so serious that they tear you apart. If you, the stay at home mom, aren't keeping the house as clean as you husband thought you would when staying at home, a discussion of the matter may be in order.
Maybe you do need to work harder at it, or maybe he needs to understand how fast children can destroy a clean room. Either way, talk it out. Being a stay at home mom is a real treat for many mothers. But it does involve sacrifice and understanding. Don't let the stresses get out of hand.
Stephanie Foster offers a free newsletter for stay at home parents and has been a SAHM for about 5 years. She also offers more advice on marriage at http://www.homewiththekids.com/marriage/.