I worked in a developing country for three years. Women’s breasts were not considered private. As a result, I saw breasts frequently. By about month two, a uncovered female breast was about as interesting to me as her elbow. There’s no reason to sexualize the breast. They are baby-feeding organs. Not to go all Freud on you, but I wonder if it’s a remnant of the breast-feeding positive feelings.
Context matters and self control exists. Yes, boobs can be arousing but if just seeing a random boob in public gives you a boner there might indeed be something wrong with you.
Hell, gynaecologist and a doctor doing beast exams look at boobs and even vaginas all day and they manage not be constantly horny.
Get your shit together.