No, I do not think Midori is romantically attracted to Haru. She will eventually see Haru as her child. It may be Haru who develops feelings for Midori, and would try to pursue her.
I get the feeling that Haru's dad is a total asshole. I am sure he forced himself unto Tsugumi and got her pregnant that way.
Tsugumi's parents probably forced her to marry him to keep up apperances.