It has been 4 years since I got married and sadly physical intimacy has drastically gone down. What should we do?

if you are still attracted to him you can definitely build on it again. try bringing in some change to your everyday routine. for instance, instead of having dinner the same old way, create a candlelight dinner at home with some wine, and spice up the night in bed. invest in some sexy lingerie and excite him. if you are open to it, use sex toys or watch some porn together to try out fun roleplays. you could also go out to a bar and enjoy some light moments, or meet up as strangers and take it from there....there's so much you can do to keep the flame on, just be creative