The British singer-songwriter’s fourth solo studio album reflects major shifts in his personal life that aren’t equally matched by musical growth.If first-dance songs at weddings counted extra toward streaming numbers, Ed Sheeran — the carrot-topped British troubadour behind such soft-rock swooners as “Thinking Out Loud” and “Perfect” — would have had a monopoly on the top of the charts for the better part of the last decade.Not that he needs much help in that department: The ubiquitous Sheeran was Spotify’s second-most-streamed artist of the 2010s (behind only Drake), and in 2017 — the year he released the blockbuster “÷” — he was the best-selling musician in the world. As a songwriter, Sheeran is something of a modern pop mathematician, gifted with an ability to reduce seemingly disparate genres (adult-contemporary pop, British hip-hop, Gaelic folk) down to their least common denominators.Since his 2011 debut, “+,” he has presented himself proudly as a hopeless romantic. “See I could do without a tan on my left hand, where my fourth finger meets my knuckle,” a then-21-year-old Sheeran sang on the sparse, unabashedly sentimental ballad “Wake Me Up.” In some sense, his fourth solo studio album, “=,” pronounced “equals” (one wonders what will happen when he soon runs out of arithmetic signs), has the potential to be the fullest realization of the Ed Sheeran ethos yet — the first since his December 2018 marriage to his childhood friend Cherry Seaborn. Honeymoon mode: Engage.“I have grown up, I am a father now, everything has changed but I am still the same somehow,” Sheeran sings on the opener, “Tides,” in a flagrant display of telling rather than showing. Musically, though, “Tides” is one of the most effective songs on the album, a stomping, surging lite-rocker arranged around a neat formal trick. After verses that rush through a list of Sheeran’s fears and neuroses, the track suddenly seems to suspend itself in midair during the chorus, long enough for Sheeran to reveal to his loved ones, “Time stops to still, when you are in my arms it always will.” (Sheeran recycles the effect later in the album, on “Love in Slow Motion.”)More than any of his previous LPs, “=” finds Sheeran mining the slick, synthesized sounds of ’80s pop. While he works again with the writer and producer Johnny McDaid of Snow Patrol, he adds a new collaborator on more than half the tracks: Fred again.., a British dance-music artist. But the retro aesthetic is most indebted to an album that is only a year and a half old, the Weeknd’s massively successful “After Hours.” His silhouette has lately cast a long shadow across his fellow male pop stars (Justin Bieber, the Kid Laroi), though it’s most apparent on Sheeran’s current hit, “Bad Habits,” a pulsating, strobe-lit lament in the tradition of a Weeknd song: “It started under neon lights and then it all got dark,” Sheeran sings, recounting another night of empty, bleary-eyed partying.Where the Weeknd’s music often revels in decadence and nihilism, Sheeran’s depictions of wild nights are often accompanied by a potent dose of morning-after guilt and the eventual possibility of redemption — usually a kind of quasi-religious salvation that can be attained through the love of a good woman. As he puts it on “The Joker and the Queen,” a music-box piano ditty on “=” that stretches a poker metaphor exhaustingly far, “When I fold, you see the best in me.”“=” is the kindest, gentlest Sheeran album, which is something of a shame. Each of his previous records had at least one song that complicated his image as a heart-on-his-sleeve nice guy, whether that was the surprisingly venomous music-industry sendup “You Need Me, I Don’t Need You” or “New Man,” his previous solo album’s sassy kiss-off to both a former flame and her subsequent boyfriend. The soulful grain that sometimes adds texture to his smooth croon is also seldom heard on this record. The driving conflict of “=” rarely strays from or goes deeper than a familiar, repeatedly stressed mantra: Life comes at you fast, but it slows to the tempo of a wedding waltz when you’re in love.An Ed Sheeran album wouldn’t be complete without a mawkish tear-jerker, and here it’s “Visiting Hours,” as in, he wishes heaven had them. Sheeran follows that indulgent weepie with a literal lullaby, the lilting, Jack Johnson-esque “Sandman.” He has grown up, he is a father now, in case you had somehow forgotten.At least the best song on the album is also the one that seems destined to be his next you’ll-hear-it-till-you’re-sick-of-it smash: “Overpass Graffiti,” a moody, synth-streaked ’80s throwback that sounds like a more melancholy update of Rod Stewart’s “Young Turks.” Here, Sheeran proves that even as a married man, he’s still able to tap into old heartbreak: “There are times when I can feel your ghost, just when I’m almost letting you go,” he sings, his voice convincingly weighted with nostalgia.Earlier, in that rush of insecurities that forms the verses of “Tides,” Sheeran admits that in the past he has been “too busy trying to chase the high and get the numbers up.” That confession might suggest that he’s ready to put algorithmic crowd-pleasing in the past, but it turns out to be an empty promise. Ultimately, “=” neither adds to nor subtracts from the trusty formula for success that he long ago worked out. It is the sleek sound of stasis.Ed Sheeran“=”(Atlantic) More