But after all when I look back upon that winter in Paris, my pleasantest recollection is of Dirk Stroeve. There was something very charming in his little household. He and his wife made a picture which the imagination gratefully dwelt upon, and the simplicity of his love for her had a deliberate grace. He remained absurd, but the sincerity of his passion excited one's sympathy. I could understand how his wife must feel for him, and I was glad that her affection was so tender. If she had any sense of humour, it must amuse her that he should place her on a pedestal and worship her with such an honest idolatry, but even while she laughed she must have been pleased and touched. He was the constant lover, and though she grew old, losing her rounded lines and her fair comeliness, to him she would certainly never alter. To him she would always be the loveliest woman in the world. There was a pleasing grace in the orderliness of their lives. They had but the studio, a bedroom, and a tiny kitchen. Mrs. Stroeve did all the housework herself; and while Dirk painted bad pictures, she went marketing, cooked the luncheon, sewed, occupied herself like a busy ant all the day; and in the evening sat in the studio, sewing again, while Dirk played music which I am sure was far beyond her comprehension. He played with taste, but with more feeling than was always justified, and into his music poured all his honest, sentimental, exuberant soul.

请教老师：

上面节选中， she must have been pleased and touched. 是对过去发生的事情的推测吧？ 那么为什么只能理解成对过去发生过的事情的推测，而不能理解成虚拟语气（与过去事实相反的假设）呢？ 

是不是因为这一句 If she had any sense of humour 用了一般过去时的陈述语气呢？ 如果是改成 If she had had any sense of humour (虚拟语气)......那么，其后的she must have been pleased and touched.

就要理解成虚拟语气（与过去事实相反的假设）呢？ 另外，顺便请教老师my pleasantest recollection is of Dirk Stroeve中is of的of这里是关于about的意思吗？  

还有，it must amuse her that he should place her on a pedestal 这里的should用法如何理解？

非常感谢！