Don't touch my breast

My wife and are soon celebrating 5 years of happy marriage with two btfl daughters. Recently, almost a year now, she started not allowing me to touch her breast and when we have sex, she she is dressed up the upper part to cover her breasts. One day when I asked she said that she had pain when I touch. My answer was, may be we need to see your doctor you may be having a serious problem but she escaped it.

Since then, I never touch them but I feel offended. When we make love I sometimes feel like we are not really enjoying it.

Dear ladies, is this normal? Should I just accept it? Your nice advises are most welcome

Updates: yes she breastfeeded both our daughters