Many people truly think that opposites attract and that is not always true sometimes they clash and have nothing in common and therefore have nothing to talk about and cannot relate to each other, it's common place to feel lost when you are living with someone for so long that you feel knows nothing about you and feel that you need to get out in order to be yourself but that isn't always the best thing for your marriage. You both may need marriage counseling to see how you can learn each other all over again and learn to better communicate with each other. There are times that your marriage is put to the test but don't give up without seeking some advice. Saving a troubled marriage is not really easy and it can take a lot of effort and work but even if you try and the marriage still doesn't work at least you know you've tried everything and can then leave with a clear conscience.
If you truly want to work on you marriage you need to look way beyond what is obvious. You need to carefully understand the cause of the unhappiness that you feel. If you're not happy anymore because you no longer have that love for your spouse then there won't be much of the marriage left to save. Communication is key to making the marriage stronger or at least telling your husband that you are no longer happy and the reasons you are no longer happy. You must hear each other out, tell him how you feel and then allow him that same courtesy, he says and believes things totally different from what you believe is the problem. Even if you have made up your mind to possibly end the marriage counseling can help you through that process also. He won't know what is bothering you if you do not tell him, this could be part of the problem you think he has known and been married to you long enough that he should know what you want and need from the marriage and it seems as though you live each day feeling like you were living with a stranger. These things can be fixed if you want them to be and save your marriage but you have to be willing to do the work and learn how to communicate and get along better and learn each others wants and needs again, it's not too late to do that.
Counseling may be your only option now so yes push him to go and if giving him an ultimatum gets him to counseling then do so. The counseling may be able to figure out why he is so quiet and not able to express himself, this counseling can help so many aspects of your issues also.