"Sunshine and smiles," Luke captioned an early October photo of the couple, who were both rocking the exact same bleach-blonde, pixie-cut hairstyle at the time. "#twinning #smiles #sunshine #happy #nofilter."
Comments from supportive fans -- mixed in with some haters -- poured into the comments section.
"Are you guys together?" one girl asked.
"Yes," Luke replied.
"Awww that's cute," the same girl responded. "Even though you're my crush, I'm still happy for you."
Another person commented on the photo, "Beautiful."
Luke told one of his followers that being in a relationship makes him happy, later adding in the comments section, "I love being happy."
Sammi also confirmed she's his girlfriend when she wrote in the comments, "Yes he's my boyfriend everyone, just not when he farts on me. #hubbiematerial."
In addition, Luke and Sammi had a playful exchange and she wrote, "I love youuu," along with three red-heart emojis.
"I believe I said I was disgusted with myself. But I did feel very, very emotionless inside. It didn't have to do with Kate; I definitely was not ready," Luke said during a March 2019 episode of Married at First Sight: Unfiltered.
"I wanted to make her happy and kind of cross that bridge, so I put myself out there and I did not have a normal response. I did not have a healthy response to it. So it was just hard and I didn't know how to handle the situation."
When Luke debuted his relationship with Sammi on Instagram, one Instagram user referenced the gay speculation and actually wrote, "Have u come out of the closet YET????"
But Luke replied, "Clearly not if I am posting with my girlfriend, but that was a good one."
It was therefore no surprise when the pair decided to split on "Decision Day" and get a divorce given they had spent weeks in an exhausting uphill battle in which Luke attempted to gain romantic feelings for Kate as she struggled to feel wanted and appreciated in her marriage.
On the April 2019 reunion show that aired on Lifetime, Kate toldMarried at First Sight's experts she was dating again and had been seeing a new guy for two months.
"It's going great! We like each other a lot. [Married at First Sight star Jasmine McGriff] has met him too. He's a teacher and a writer. He's very handsome and genuine... He wrote a book and shared it with me. He's a great writer," Kate gushed at the time.
But Kate's post-show romance apparently fizzled out shortly after her appearance on the reunion special.
"We had a talk and I was still married, technically, at the time, and I had one week of processing time. He also had just gotten out of a few-years relationship, and we just decided to go our separate ways... So I am single and loving it right now!" Kate admitted on Instagram after the special aired.
There is no sign Kate is now in a relationship of her own on Instagram.