it was in the town where they first met that they got marrie

可以.、
因为用that 就变成了强调句.强调遇见的地点.
需要注意的是,强调句型中各部分都是完整的,也就是说当去掉it is/was ……that 时,意义还完整.
就如这句,it was in the town that they first met.
变成 in the town they first met.