"That's what attracted them out there in the first place."

"That's what attracted us to each other in the first place."

That was why she had been attracted to him in the first place.

It's what attracted her to movies in the first place.

That was what attracted him to her in the first place.

That, of course, is why you were attracted to her in the first place.

"I'm not even sure what attracted me to her in the first place."

Isn't that what attracted you to me in the first place?

Wasn't that what had attracted her to him in the first place?

"Because if the conditions that attracted them in the first place remain, then they will return."