“For the past almost four years I have been living a lie. My husband has no idea that I am involved with my boss. His wife is oblivious to our relationship. If I bring this all out in the open it will destroy two families. What can I do?”
There are no easy answers to this difficult circumstance – but your secret liaison is distorting your view of everything. Understandably, you appear to want to fix something while also keeping it hidden – and I am not sure this is possible. A good place to begin would be with removing yourself from the predatory behavior (it is predatory BECAUSE he is the boss) of your boss. Resign. Look for another job. Do whatever it takes to come out from under his influence. Way will lead to way – and, while you are yet under his spell, you will not be able to see your way forward. Come clean first with yourself. Then we can start to talk about what needs to be done about the other victims in this sad scenario.
You are right – it is a temporary solution. How long can you both live like this? The bedroom is the crucible, and I’d suggest that after some meaningful discussion (including helpful conflict) both of you assess how love can realign (re-shape, change, modify) itself. You will not be the first married couple to live separate lives while sharing a house, but this does not make it less regretful. Talk. If you stop talking you could become so accustomed to living this way you will never grow beyond this point. 
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