"Can't wait to make endless memories with u & forever cherish you with all my heart," Max Ehrich wrote to the pop star

Demi Lovato; Max Ehrich
Demi Lovato and Max Ehrich
| Credit: Max Ehrich Instagram

Max Ehrich is making sure fiancée Demi Lovato is feeling the love on her birthday.

On Thursday, the actor shared a series of PDA-packed photos on Instagram to celebrate Lovato's 28th birthday, including a sweet caption about his passionate feelings for his soon-to-be wife.

Ehrich featured a variety of kissing selfies of the pair, as well as a few shots from their recent engagement on the beach in Malibu.

In the first picture, the 29-year-old actor is seen giving the "I Love Me" singer a smooch on the cheek, whereas many of the other romantic pictures see the two locking lips.

The actor also featured a sweet shot of the couple from their June weekend trip to Joshua Tree National Park in California.

Ehrich also added a candid shot of the couple cuddling in bed together with Lovato's pooches, Batman and Ella.

"words fall short baby," Ehrich began the heartfelt caption. "you light up this world & i am the luckiest man alive to call you my fiancé. i keep falling more in love with you & your pure heart & soul every moment."

The Young & The Restless star gushed, "can't wait to make endless memories with u & forever cherish you will all my heart."

"happy 28th, my angel @ddlovato 💘🎂🥳," he concluded the post.

Demi Lovato; Max Ehrich
Demi Lovato and Max Ehrich
| Credit: Max Ehrich Instagram
Demi Lovato Max Ehrich
Credit: Demi Lovato/ Instagram

The happy couple has been enjoying engagement bliss since Ehrich popped the question in July, less than four months after PEOPLE confirmed they were dating.

Earlier this month, the pop star and her actor fiancé stepped out at Nobu, the popular restaurant in Malibu, California, to celebrate their five-month anniversary where they previously celebrated their engagement and a recent date night.

Dressed in a bright pink dress that she accessorized with a pair of black heart-shaped earrings and a similarly shaped Chanel bag, Lovato and Ehrich met up with Nikita Dragun for the dinner outing.

"It's the ring for me... it's the supportive friend for me... it's the 5 month anniversary for me," Dragun said as Lovato reshared the image to her own account and wrote, "I f------ love you," alongside an emoji blowing a kiss.

Demi Lovato and Max Ehrich anniversary
Demi Lovato and Max Ehrich

Ehrich also shared a photo from the intimate night out, writing, "i love u baby happy anniversary 💍" in his own social media post.

In July, Lovato and Ehrich enjoyed a romantic evening together at the popular Malibu hotspot alongside a small group of close friends to celebrate their engagement.

Demi Lovato and Max Ehrich have a date night
Demi Lovato and Max Ehrich
| Credit: Demi Lovato/Instagram

"They enjoyed a romantic dinner date on the patio overlooking the ocean," a source previously told PEOPLE of their engagement night. "Demi wore her huge engagement ring. She is still glowing. Max is very sweet to her. You can tell he just adores her. They shared several dishes and had a fun dinner. Demi was giggling as they chatted. They are beyond cute together."

"Demi could not stop smiling. She said the engagement was a total surprise. You could tell it was both exciting and overwhelming for her. She even got teary-eyed a few times. It was all very emotional," the source said. "They kept kissing throughout the dinner. They are a very cute couple. Demi could not stop staring at her ring — it's huge and absolutely stunning."