Krewella Lawsuit -- I'm Being Forced Out ... For Being SOBER

Mega-popular EDM group Krewella has no place for people who don't party ... because a former member claims he was kicked out for being too clean.

Kristopher Trindl says he formed Krewella back in 2010 with former girlfriend Jahan Yousaf and her sister, Yasmine ... but now says the women want to morph the group into a duo. In a new lawsuit, Trindl says the girls came up with a lame reason for kicking him out ... that he acts too depressed.

Trindl partied plenty before he went to rehab last year. After rehab, he says the women started treating him differently ... and he believes it's because he became a teetotaler.

He does admit relapsing twice and missing a major event -- the Electric Daisy Carnival. Hmmm.

Trindl says to add insult to injury, the girls put up a billboard of themselves on the Sunset Strip.

Trindl says when he came back from rehab, the sisters didn't like the new, sober Kris ... because he no longer drank and partied. He claims they even staged an intervention -- to try to force him into rehab again -- because they thought he was depressed and needed treatment.

He says it's clear ... they just want him gone so they can take his one-third share of Krewella's earnings. He is suing the sisters for more than $7M in damages.