You didn't say it made her uncomfortable to nurse in front of others or in public...you just said she doesn't because her husband didn't like it. Which IMO is childish.
Breasts are sexual, breasts are for feeding babies, but breasts being used while feeding a baby is not sexual therefore there should be no issue at all. (A lot or a little or none showing doesn't matter).
Katie, mom to Olivia (97), Veda (98), Franky (2004), Wendy (2005), JoHannah (2007), Thea (2009) and Sunny (2011)