You’ve just been sacked with divorce papers from the woman who in this scenario hasn’t been paying the bills for some time.

Nothing will increase the cost of your case faster than failing to weigh the cost of the fight. Know what to fight about and what to let go:

1. Affairs and other reasons for divorce. Won’t the judge throw the book at her if she’s been sleeping with her yoga instructor for the last year? (or, uh, will you get in trouble because you’ve been sleeping with her yoga instructor?)  Legally speaking, the simple answer is: No.

Affairs and bad marital behavior are not something that the courts want to hear about (unless those wrongs pertain to custody issues). For the most part, that means that her “lotus position” with the yoga instructor – as emotionally devastating as that might be for you – isn’t going to change the division of assets. Chanel your energy to other areas of the case and you won’t waste legal fees fighting about misdeeds that don’t change the financial break-down. For example: she bought the yogi a Rolex, which is a mis-use of marital funds that you can recapture.

2. Alimony. If she and the yogi are shacking up together will that hurt her claim for Alimony? Short answer: Oh yeah! Courts won’t want to award much alimony when the spouse seeking it has moved in with (and is being supported by) a romantic partner, especially when that person is paying her living expenses.

We talk about alimony as a tool to help one spouse get back on her feet when the other is earning much more, particularly in cases where one was a home-maker and sacrificed a career (or needs training to get back into the job force). Rule of thumb: the longer the marriage, the longer the support. But, courts, for the most part, are moving away from the idea of life-time alimony. And, when she may be getting support from a new romantic partner, many courts find that means alimony should end.

Some of the best advice for women (and worth repeating to men whose wives stay at home): getting a job will empower her to make her own decisions and be less reliant on you in the long-run. If she’s asking for alimony, consider offering it as a short term solution to helping her get back on her feet. Don’t roll over on the amount or duration, but remember that alimony is tax-deductible for you in many cases!

3. Child Support. Wait, you said if she’s living with Thor, her Swedish yoga teacher, I don’t have to pay, right? No. I said you don’t have to pay her – your kids are still your responsibility!

My take-away from most child support schemes is that the children are the focus of the court’s concern, and not your bottom-line. Let’s get a little philosophical: maybe you feel like the “child doesn’t need” that level of support. But the extra funds might get your ex- into a better apartment, which in turn gets your kid into a better apartment and, perhaps, a better school district with peers more likely to attend college. See how these issues are tied together?

But what if she’s just spending the money on fancy shoes and fake boobs? Well maybe those tits will land her a new doctor-husband, who lives in a better apartment, which gets your kid back in a better apartment increasing the kid’s chances to go to college… #meta.

Maybe child support feels unfair, or maybe you just need a new way of thinking about spending for the child. Either way, use your legal fees on something else (like terminating alimony because of the doctor-husband; or showing that the boob-job was a mis-use of marital funds!)

4. Retirement accounts. Your employer and you have been setting aside money for your retirement from your job. Retirement savings may feel personal, but they are really marital income.

But she hasn’t worked so why should she get a pension? Really? She’s helped you get where you are – by doing your laundry, taking care of the kids and burning you dinner. These are all time-consuming tasks – and trust me, they interfere with the ability to work long-hours. You didn’t make it where you are alone my friend.

In New York, the law provides her with half your pension from the date of the marriage to the date of the Summons for Divorce. If you started working before the marriage, that income saved in those years are yours. But, in all honesty, pension division is complicated and you will need forensic accountants to help with the process. So, on top of sharing your pension, be prepared to pay an expert to help value and divide those assets.

Have you wasted fees fighting about affairs or your wife’s plastic surgery? Discuss in the comments.