Simply being a previous client doesn't automatically mean that the lawyer is prohibited from representing your ex-wife. It really depends on what is being litigated now and how the facts of your unique situation come into play between the two separate representations. Take a look at the link I provided below (Professional Conduct) for your reference to the applicable Indiana Rule of Professional Conduct, Rule 1.9.
You raise some interesting issues with your question. Much of the simple answer depends on the type of issues you face in your dissolution of marriage. Right off the bat, your former attorney may not take information he learned from your prior representation and use that against you. No confidential information may learned from the prior case may be used in any capacity in the subsequent case. So, if you faced a custody battle, your difficulty remaining employed (learned from your bankruptcy) could not be used as a means to challenge your claim to custody. that's just one example. As an Attorney from a smaller town in Indiana, I know that some times lawyers will jump have former clients as defendants. The key issue is are they attempting to use information from their first relationship against them.
If your Dissolution of Marriage is relatively uncomplicated, i.e. no children, no Real estate to split, no debt to split, it seems quite unlikely that contested issues would arise that might give your attorney opportunity to utilize your private information against you.
On the other hand, Indiana is keen to avoid the appearance of impropriety. Thus, if you have significant reasons why you feel the attorney's representation of your spouse is inappropriate, then you should raise the issue directly with the attorney. You should write to the attorney and explain your discomfort and ask him/her to withdraw from the representation of your spouse. Although they may not be legally required to do so, the possibility of appearing to have done something inappropriately will discourage them from taking the matter to completion.
Best of luck to you.