never once ------(老两口互相争吵）since they were married 40 years a

since 后是过去时,之前是现在完成时.若是跟段时间,还可以用一般现在时.
如：Great changes have taken place in the city since we met last time.
It's ten years \ has been ten years since we met last time.
你问的这道题,用过去时,讲述的是一件过去的事,故可以用一般过去时.“他们从四十年前结婚起,老两口就常争吵.”
不可以用过去完成时.