Roles and Conflict

I've been reading a lot of Anthony Trollope lately, and thus found myself thinking a fair amount about what the 19th century thought to make a good, or a bad, marriage.

One of the major sources of marital strife in Trollope novels is when the husband or wife is in the habit of interfering in the other's business. After watching this play out between several of his troubled couples, it began to strike me to what an extent Trollope's idea of a happy marriage is rooted in the assumption that the husband and wife have separate spheres. The wife manages the children and the household affairs. The husband manages his profession and the estate. So long as each is happy to leave the other in charge of their domain, there is harmony regardless of how affectionate the couple actually are. And when they do attempt to manage each other's domains, conflict results even among the more affectionate couples.

I don't advocate a strict separation of spheres in marriage. MrsDarwin and I are one of those couples that prefer doing most things together. But it does strike me that having the goal of "50/50 split" in various areas of duty is often problematic, since one so often ends up feeling like one is the one struck doing 55% while the other does only 45%.

To what extent does the modern ideal of men and woman having interchangeable roles in a marriage actually create more conflict by setting the husband and wife up in competition to one another?