Respect her choice, not doing so would be rape.
That is the legal answer and I would agree. But, for a solution to the issue, it is going to come in the form of investigatory conversations about what her mental hangup is. If this is simply a biblical issue on her part then teach her the word of God! Otherwise, this is not easy as it will be dealing with her feelings and not based on any facts (usually). As a man, you will have to figure out how to make her "feel" that she wants you.
She will NOT be able to tell you what it will take.
She will not know the answer to this herself. It is
vital that you do not try to appease her as you go through this process or she will lose respect for you and the situation will retard even further than it is now.
A woman wants to see her
husband is firm, kind, logical and purposeful. The conversations are not really to figure her out although, there may be some breakthrough there, they are to demonstrate these traits to her as you discuss the situation. Through your kindly conversations that are firmly based on your foundational truths, she will likely come around and you will once again have a submissive wife.
If she refuses to engage in the conversations, then you can begin to correct her. This should be done in a matter of fact way that informs her that you want peace between the two of you. That you want intimacy between the two of you. That you are willing to have conversations to get to that point but
until she is willing to follow your lead, you will not be pretending that all is well between the two of you.
Then begin to remove her "service" from your day to day. If she makes you coffee, make your own or have your other wife do it. And continue these types of things, slowly escalating the number of things you remove. If she loves you, she will not want to lose the opportunity to serve you.
This is an effective correction for someone that loves you. If she does not, she may relish the freedom and sadly, you may need to make her freedom official via a divorce.
DO NOT RUSH the process. If you love her, you should be seeking to have the conversation that restores the relationship back to it's proper order.
I pray that this blesses your relationships!