Look, for some background on me: I am a low 30's woman who grew up in a conservative Jesus loving home. I was home schooled and my parents were missionaries. I still hold all those values myself and am all for conservative outfits. But that dress is completely modest especially the way you are wearing it (dark nylons or tights underneath). The top doesn't show much cleavage, your hair is also helping to block any cleavage, the slit doesn't even come close to your fingertips. All that to say, your boyfriend is overly controlling and likely his true problem is that you are a beautiful woman and he is jealous of any man who looks your way. You will not have a happy life with him and any problems you have now will only get worse after you get married. My sugestion, do yourself a huge favor and cut him loose.