First movie: Lydia is a teenager, and Beetlejuice only tries to marry her as a means to an end.
Second movie: Lydia is a middle-aged woman with a teenage daughter and Beetlejuice pines endlessly for her and considers her the one true love of his life.
Third movie probably: Lydia is an actively decaying ghost with pieces falling off and Beetlejuice is so supernaturally horny for her that he trips over his own erection and falls face first down a flight of stairs and dies a second time.
Y/N: my afterlife before you was nonexistent. Astrid, you are the light at the end of my tunnel. The closest to heaven I’ll ever see. You gave my dead heart a reason to beat again. Will you marry me?
Beetlejuice starting a bio-exorcist business wasn’t just about proving he’s a solid, dependable ghost that will take care of Lydia and her emo teenager. It was also an excellent way to get her attention and further support her career. In taking on customers, Beetlejuice creates prime chaos fit for television, and it’s perfect for Lydia’s show. Plus, he can keep her safe. Think about how the segment at the start of the movie shows a ghost wreaking havoc, putting a dog on a fan, and laughing maniacally. But we never SEE the ghost, and despite the chaos, Lydia comes out unscathed.
Was discussing with my mom about Beetlejuice and Lydia. She was talking about how the 2nd song he "sings" is about saying goodbye to a love affair, waxing nostalgic. So it just feeds into my opinion that Beetlejuice never expected Lydia to go through with the wedding after all. He was saying goodbye.
The loophole that Astrid found? It seemed glaringly careless of him. No ironclad contract? He didn't even try to stop them from sending him back like he did in the first movie.
He truly loves Lydia and actually selflessly helped her save Astrid. I rest my case.