Q. Can a woman trim her eyebrows and shave or pluck hairs from her face during Sefirah days, so she will not become unpleasant to her husband?

A. Poskim indeed permit the above when one is dealing with maintaining pleasant family relations (See Shulchan Aruch Y.D.390:5, Igros Moshe Y.D. 2: 127, Nitei Gavriel 49; 10-14, Kovetz Halochos 10: 1,2, and others.

Likewise Shulchan Aruch (O.H. 551: 13) also permits shaving mustache hairs that interfere with eating during the Three Weeks.

Horav Shlomo Miller’s Shlit’a opinion is similar.
Rabbi A. Bartfeld as revised by Horav Dovid Pam, Horav Aharon Miller and Horav Chanoch Ehrentreu Shlit’a