Yesterday I read not one but two blog posts about your boobs. Both along the lines of blaming another woman for issues in their marriage. One was titled my husband doesn't need to see your boobs. Well guess what honey your husband will see other peoples boobs. Or do you avoid all pools, parks, beaches, basically become a shut in during the summer? Get over it. Some chick posting a bikini pic on Facebook is not destroying your marriage. Really it is your own insecurities that are going a damn good job of that.
Look we all have problems in marriage. Hey it's not a fairy tale everything is perfect, but blaming others does not help. You need to look at what's you are doing, what your husband is doing, not bitch about the young hot thing who's wearing a bikini on the beach.
If you don't like how you look do something about it. Bitching on the internet does nothing. Really though if it is that big of a issue that you ban your spouse from social media during the summer I highly suggest you seek professional help. It's not good for you, your husband, your kids, or your marriage.
Here's the deal us married people can see a decent looking person and think wow he/she looks good. We can even think in our heads if I could just have 5min with him/her. That's normal and guess what it doesn't affect our marriage. None not at all. It's a passing idea. It has no say in how we view our spouse.
So it's not that your husband doesn't need to see her boobs. You need to lighten up and get over it.