I am very sorry for your situation. I highly recommend you urge her to enter marital counseling. Hopefully you two can mend the fences.
Tennessee has both a no fault and fault option when seeking divorce. However, a no fault divorce must be uncontested and based upon irreconcilable differences. If both parties do not agree to the divorce then one party must proceed and prove fault on the other party in order to achieve a divorce. Although I have seen divorce lawsuits successfully defended (the divorce was not granted), it is a rare occasion when someone petitions for a divorce and is not granted one.
If the courts are left to decide every issue then you can expect a fairly even divide of the children's time between parents. This assumes the children wish to spend equal time with each parent, each parent has been equally involved in the children's' lives, and that such an arrangement is in their best interests. Tennessee uses a best interests of the child standard of review. Child support will be determined (even with an equal custody split) using a standard formula that takes into account the respective earnings of each party. You can probably count on her insurance continuing to cover the children... but not you.
The courts will divide property as evenly as possible between the parties. This means that the courts will split evenly every asset that can be split and will then make an equitable divide of the remaining assets that cannot be evenly divided. For example, you may be awarded the marital residence (with $200,000 equity) and your wife may then be awarded her undivided retirement savings ($100,000 total value) and the family vacation home ($100,000 equity) to offset the value of the marital residence. Fault plays no role in the determination of asset division in Tennessee divorces.
Alimony is possible in a divorce action but is not very common in Tennessee unless one party has been the primary earning source while the other party sacrificed their earning capacity to care for the parties' children. In that scenario the courts will frequently award a rehabilitative alimony amount to help the disadvantaged spouse rebuild their earning capacity. Also, if one spouse suffered a disability or had no ability to rehabilitate their earning capacity then a more permanent alimony may be established.
Obviously you need to consult a good local attorney and prepare yourself for any eventuality. There are several things that need to be done before the filing of a divorce to preserve an advantage in the case. So don't wait until she files... get a lawyer now.
Here is a pretty good summary of divorce law in Tennessee.
Please reply if I can help further.
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