Warning signs pointed to Ariana Grande and Pete Davidson's split: Where did it go wrong?

Ariana Grande and Pete Davidson’s breakup has left fans shaken. OK, shaken may be an exaggeration, but it was pretty sudden, given they were talking wedding plans just last month.

So where did it go wrong for the “No More Tears Left to Cry” singer, 25, and Saturday Night Live star, 24? Take a look back at the couple’s love story — there have been signs for weeks that a split was looming.

March 2016: Grande and Davidson’s spark actually goes back a few years ago when the singer appeared on an episode of SNL. “We never exchanged numbers or anything. We weren’t even like friends for the longest time,” she recalled over the summer. “But I had the biggest crush in the whole world on him the whole time, like forever. Like, my friends used to make fun of me for it, all that stuff.”

Grande continued, “I left his writers’ room when we were like writing skits and stuff for the show, and my tour manager … was in the hallway, and I’m not a crushy person. I don’t have crushes on people I don’t know. I’m not crushy. But I left and I like jokingly said to my tour manager, I was like, ‘I’m marrying him. 100 percent. I’m literally marrying him.”

Davidson remembered the encounter quite well too. “I was obviously ogling and trying not to be creepy,” he told Variety.

May 2018: Timing is everything. Grande and Davidson both found themselves single after splitting with Mac Miller and Cazzie David, respectively. So, her manager Scooter Braun played matchmaker for the pair.

“Scooter told me [Ariana] has somewhat [interest] in me,” Davidson told Howard Stern of their courtship. The singer invited him to her New York apartment to hang out, something he thought was a pity invitation, after her Met Gala appearance on May 7. They shared their first kiss that night and it was game on.

The public became aware of their relationship about three weeks later. A source told People that their relationship had “just started,” adding that it was “very casual.”

Grande and Davidson cemented their relationship on Instagram — one of their favorite modes of expressing their love, particularly in the comments section of their posts.

June 2018: From casual to serious! Davidson got a tattoo of a bunny-ear mask similar to the one Grande wore on her Dangerous Woman album cover. (The pair also got matching tattoos on their hands.)

And then the couple went from serious to engaged. Reports swirled that Davidson had popped the question, something he confirmed on The Tonight Show With Jimmy Fallon. “It’s so lit,” he exclaimed.

Davidson proposed with a 3-carat diamond ring rumored to be worth around $100,000. “I didn’t want to do something corny,” he told Variety. “We were in bed hanging, after watching a movie. I was like, ‘Will you marry me?’ It was really dope.” He continued, “I’m still convinced she’s blind or hit her head really hard. Something is going to happen, and she’s going to be like, ‘What the f*** is this thing doing around?’”

The couple moved in together in New York City, with Grande reportedly dropping $16 million for a 4,000-square-foot apartment.

August 2018: Grande and Davidson’s love parade went cross-country. Despite a few trolls on social media, things seemed to be going well for the couple. The singer dropped her fourth album, Sweetener, which included a tribute to her fiancé titled “Pete Davidson.” While on a promotional tour, Grande seemed excited about wedding planning.

“We’re gonna take our time to plan it,” she said on Good Morning America, adding that the wedding would probably be sometime in 2019. “My friends and I, my mom [Joan] and everybody have been brainstorming and sharing ideas and stuff. It’s really fun. … I’ve never spent this much time or energy planning something personal that feeds my soul so much, and my heart. I’m gonna cry, I’m just so excited. It’s sick, it’s really fun.”

September 2018: On Sept. 7, Grande’s ex-boyfriend Mac Miller died from a suspected overdose. Miller and Grande had dated for about two years before splitting in the spring, and the singer’s world was rocked by the devastating news.

“I can’t believe you aren’t here anymore,” she wrote in a heartbreaking tribute. “I really can’t wrap my head around it. … I’m so mad, I’m so sad I don’t know what to do.”

In the wake of Miller’s death, Grande and Davidson both skipped the 2018 Emmys, where they were due to appear. She was also booked as a musical guest on Saturday Night Live but pulled out for “emotional reasons.”

Grande announced that she was taking some time off. “Given the events of the past couple of years, Ariana is going to take some much-needed time to heal and mend,” a rep said on behalf of the singer. “She will be staying close to home and using this period to spend time with her loved ones and work on new music without deadline. She thanks her fans for their understanding.”

Davidson was by his fiancée’s side during the difficult time — and the wedding was still on. “We’re working on it,” Davidson told Howard Stern in September of their plans. “We have a game plan.” He added, “I’m just f***ing lucky, and I hope that I don’t wake up.”

Still, Grande was struggling, which was evident in a series of emotional tweets.

Yet Davidson took a more lighthearted approach when discussing their relationship. During SNL’s “Weekend Update” on the Sept. 29 premiere, he even joked about their eventual breakup.

“Obviously I wanted [a prenup], you know, so God forbid we split up and then she takes half my sneakers,” he quipped. “No, look, I’m totally comfortable being with a successful woman, I think it’s dope. I live at her place.”

He continued, “Last night I switched her birth control with Tic Tacs. I believe in us and all, but I just want to make sure that she can’t go anywhere. …

“You know, I don’t even get royalties for that ‘Pete Davidson’ song?” he laughed. “Like, if we break up, and we won’t — we will — but we won’t. I’m kidding. But like, in 10 years if God forbid that ever happened, there will be a song called ‘Pete Davidson’ like playing in speakers at Kmart, and I’ll be working there.”

The couple was photographed together around New York City and continued to leave flirty comments on each other’s Instagram posts. So … all was good? Not so fast.

October 2018: After a difficult month, there was another major sign of possible trouble in paradise for the couple: Davidson appeared to cover up his Grande-inspired ink behind his ear.

However, he seemingly put an “A” next to the bunny-ears-turned-heart-tattoo, so fans weren’t entirely convinced that this was a sign of trouble. But Grande was still obviously struggling.

Over this past weekend, the singer pulled out of another commitment; she was set to perform at a cancer benefit hosted by manager Scooter Braun. “Someone I’m very close to was supposed to come sing for you today, and because of things that she’s going through, she couldn’t be here today,” Braun said cryptically. “And while I was frustrated, being the manager, my wife, being who she always is, just looked at me and she goes, ‘She needs this time.’”

Instead, Grande was backstage at SNL on Saturday supporting Davidson. But just one day later, the pair called it quits. “It was way too much too soon,” a Grande source told People. “It’s not shocking to anyone.”

Grande broke her silence post-split on Monday but made no mention of her ex-fiancé in an Instagram post.

Perhaps we’ll hear from one of them soon.

Read more from Yahoo Entertainment:

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• Kim Kardashian reveals she’s been having ‘traumatizing’ dreams about daughter North West

• Ariana Grande and Pete Davidson have reportedly called it quits