I split proceeds from home sale with ex. where do i enter that so i don't get hit with the total capital gains tax?

You will have no reporting requirement related to the sale of your primary residence if you meet the gain exclusion requirements unless you received a 1099-S from the sale.

See this IRS link for more information on the exclusion:

https://www.irs.gov/taxtopics/tc701.html

If you did receive a Form 1099-S for this sale, that means the IRS also got a copy and you will need to report this information into TurboTax. (But don't worry, TurboTax will guide you on entering this information on your tax return). Also only enter your portion of all amounts if you need to enter this sale in TurboTax

To enter the sale of your home in TurboTax Online or Desktop, please follow these steps:

1. Once you are in your tax return, click on the “Federal Taxes” tab ("Personal" tab in TurboTax Home & Business)
2. Next click on “Wages & Income” ("Personal Income" in TurboTax Home & Business)
3. Next click on “I’ll choose what I work on”
4. Scroll down the screen until to come to the section “Less Common Income”
5. Choose “Sale of Home (gain or loss)” and select “start’
6. You will want to use the "Easy Guide" to determine the adjusted basis on this home  (screenshot #1)

Say "yes" that you sold your main home and TurboTax will guide you on entering this information.  You will need:

• The date you sold your home and the selling price (from your closing statement)
• The date you bought your home and the purchase price (from your closing statement)
• The cost of any major improvements you made, so we can deduct them for you
• Form 1099-C if you sold your home at a loss (short sale)

Just remember to check the box to have your home sale reported on your tax return but ONLY if you receive a 1099-S (see screenshot #2)