If you've found your soulmate, then just being able to marry that person means you're already lucky. The day you tie the knot really doesn't matter.
But since you've already opened this page, let's see which should be the best day for your wedding.
February 14th is a popular choice for weddings in many countries, including Japan, because that's Valentine's Day.
Another popular day is November 22nd. That date, 11/22, comprises two 1s and two 2s. In Japanese, '1' is ichi and '2' is futatsu. Abbreviating those two numbers to i and fu can, with cute imagination, translate 11 22 to ii fufu which means 'lovely couple'.
That has nothing to do with Rokuyo though...
As explained here, each day of the Rokuyo calendar is associated with luck. The Rokuyo days Taian and Tomobiki are the most popular to tie the knot and Butsumetsu is the least favoured.
However, in the current economic situation, money has become a significant factor in deciding the best day for a wedding in Japan. You might get a discount from the wedding hall if you have your ceremony on Butsumetsu.
Due to the passing of the baby boom 30 or so years ago, fewer people will reach the marrying age from now onwards. Therefore wedding companies face the double problem of a shrinking market and an economy that's weakened since the 1990s.
In response, some companies offer a special discount to people who use their services on a Butsumetsu day. The cost of the incentive is more than made up by the efficiency gained by the more balanced use of resources throughout the week. Those who choose to marry on a Butsumetsu are more likely interested in saving money, rather than being superstitious.
That being said, Taian and Tomobiki are still the most popular for weddings in Japan. And some older family members who retain strong superstitions might encourage the couple to choose a Rokuyo-friendlier day than Butsumetsu.
If so, the couple should book their day at the venue before it fills up.
(See also Lucky Horseshoe and Western-style Weddings in Japan)