WALL STREET JOURNAL, KRISTINA PETERSON and NATALIE ANDREWS

Adam Spanberger didn’t quite fit in with the crowd when he showed up to the 107th annual First Lady’s Luncheon wearing a dark gray suit and white shirt.

“Most people thought I was Secret Service,” said Mr. Spanberger, who as the husband of Rep. Abigail Spanberger (D., Va.) attended the fundraiser at the Washington Hilton hosted by the Congressional Club, a group of current and former spouses of lawmakers and other high-ranking officials. Of the roughly 1,800 guests, he estimated, fewer than 100 were men. All were sent home from the mid-May event with a quilted Vera Bradley gift bag containing a scarf and a bracelet, among other items.

“That’s just going to be so pretty on you,” Mrs. Spanberger joked, holding up the bracelet as she sifted through the bag’s contents a few hours later.

The record-breaking total of 127 women who now serve in Congress has gotten a significant amount of attention. The corresponding shift in the demographics of their spouses hasn’t. Some of the newly elected women are single. One, Rep. Angie Craig (D., Minn.) has a wife. But on the whole, they have added an influx of new congressional husbands to what traditionally has been a very female group.

Washington at times has been slow to adapt. Charlie Capito, husband of Sen. Shelley Moore Capito (R., W.Va.) and managing director at a financial services company, also was mistaken for security at the Congressional Club lunch—until he delivered the invocation as its first male vice president. While he has witnessed some change since Mrs. Capito came to Washington in 2001—the Republican Congressional Spouses Club no longer sends out its correspondence in pink envelopes—he said he didn’t mind bringing the quilted gift bags home to his wife.

“I have at least one very eager recipient, so it’s okay with me,” Mr. Capito said. “I just put it over my shoulder and go right down Connecticut Avenue.”

Rep. Mikie Sherrill (D., N.J.) giggled with her husband, Jason Hedberg, about the 48-inch dolls in the Congressional Club that sported dresses matching the first ladies’ inauguration gowns.

“I said: ‘Well honey, why don’t you just hang out with you and the first lady dolls—that’s a nice way to spend the afternoon’,” she said. Her husband has taken to his new role, jumping on a text chain with several other spouses.

To be a congressional husband is to be outnumbered. Matt Miller, husband of Rep. Carol Miller of West Virginia, the sole Republican woman elected to the House in 2018, was the only man present among the lawmakers and aides on a congressional trip to Guatemala in April focused on human trafficking.

The two celebrated their 46th wedding anniversary on the trip with a cake—then went their separate ways. “She flew back to D.C. and I flew back to Huntington,” said Mr. Miller, who works with his two sons at the family auto dealership

The Democratic Spouses Forum has been evolving to accommodate more husbands for years, said its president, Lisa McGovern, the wife of Rep. Jim McGovern (D., Mass.). Around 2004, the group overhauled its “Big Sister” orientation to a more gender-neutral mentorship program, she said.

“It’s such a weird lifestyle” to be married to a member of Congress, Mrs. McGovern said. “Other spouses get it in a way that my own sister that I talk to every single day doesn’t get it.”

The transition is more stressful for some than others. Mr. Spanberger said it now was easier to find out the location of his wife, who previously worked as an undercover agent for the Central Intelligence Agency and would leave for operations without a personal cell phone.

Ms. Spanberger would tell her husband, who works on satellite systems for a defense contractor, ‘’I’ll be back in three days. If I’m not, call this number,’” he recalled. Now, he said, “she’s got a whole staff of like 17 people that know exactly where she is and if they don’t know where she is, I can go on Twitter or social media.”

Retired Army Col. Dave Moore often commutes from Washington, where he works at the Pentagon, to Michigan on the same congressional schedule as his wife, freshman Democratic Rep. Elissa Slotkin. When he’s there, he takes other titles: driver; aide; and confidant. In Washington, he has used the coveted spouse’s pin, which allows him to skip the security line, to help his wife’s staff finish errands, including transporting hot-dog buns for an office party.

“I was the hot dog bun sherpa,” he said. “That was key.”

P.J. Cunnane, a former bicycle company chief executive who met his wife, Rep. Madeleine Dean (D., Pa.), working on a political campaign in the late 1970s, said her election has affected their long-running political debates.

“I’ve learned to defer to her staff,” Mr. Cunnane said.

“I thought you were going to say defer to me! How about me?” his wife demanded.

Most female lawmakers said they still were sometimes mistaken for the spouse rather than the elected official. Bart Houlahan, husband of Rep. Chrissy Houlahan (D., Pa.) and head of a nonprofit focused on corporate social responsibility, said that at campaign events he had taken to wearing a nametag labeled “Mr. Chrissy.”

“I often get confused for the security guard or the body man or chief,” he said. “It’s pretty rare that people assume I’m Chrissy’s husband.”

Mrs. Capito said she occasionally took advantage of the confusion when unknowing reporters asking her husband for comment. “They’ll stop him and I, of course, will keep walking,” she said. “He’ll wait it out and contemplate it and say, ‘She just went that way.’”

The surge of newly-elected women has occasionally prompted a mix-up in the opposite direction.

Ms. Dean said she was waiting to use the ladies’ restroom during new member orientation, when both lawmakers-elect and their spouses were wearing lanyards.

“I saw a woman in front of me with a lanyard [and asked] ‘Oh, what district are you?’ and she said ‘no no, my husband is…’” Ms. Dean said. “I just presumed of course she was the member of Congress.”