A new study from Fidelity Investments finds that fewer than half of couples make investment decisions for retirement together, and wives lag behind their husbands in terms of retirement education.

The Couples Retirement Study, conducted in May 2011, finds that only 41 percent of married couples make retirement investment decisions together, and only 17 percent of couples are totally confident that either spouse is prepared to assume responsibility for the couple's retirement finances, if necessary. 

But that's not where the trouble ends. Thirty-three percent of couples either don't know or can't agree where they'll retire, and another 62 percent of couple nearing retirement don't agree on their anticipated retirement ages. Close to half (47 percent) disagree whether they'll continue to work in retirement, and 73 percent of couples can't even determine whether or not they have a detailed retirement income plan. 

One of the major contributing factors to the disagreements and lack of communication may be that wives are often not as involved or are less knowledgeable about their retirement finances than their husbands. The problems are especially noticeable when it comes to financial confidence, engagement, awareness, and approachs to investing.