Melissa Etheridge Domestic Partnership War With Tammy Lynn Michaels -- SETTLED

Melissa Etheridge has FINALLY settled her 2 year war with domestic partner Tammy Lynn Michaels ... TMZ has learned.

The former couple hashed out an agreement last night as part of court-ordered mediation.

The settlement covers both partner and child support. As TMZ first reported, Tammy had been receiving a total of $23,000 a month from Melissa, but claimed she was barely scraping by and that Melissa could afford to pay more since she was raking in $177,882 a month.

Sources connected with the couple tell TMZ ... under the terms of the settlement, Tammy will net more than the $23,000 a month, though we don't have the exact figure.

As for who gets the 5-year-old twins, Johnnie Rose and Miller Steven, we're told Melissa and Tammy will share joint custody, with adjustments when Melissa goes on the road.