Traditionally, the answer to this question has been yes. The obligation to pay maintenance has not terminated in Colorado just because either the payer or recipient is in a new relationship. This is confusing to people because maintenance does automatically end if the recipient remarries [although a remarriage by the payer does not limit the obligation to pay maintenance].
There are circumstances in which the recipient of maintenance is supported by a new “significant other” to the extent that this might end their need for maintenance. For anyone contemplating moving in with a significant other while receiving maintenance or whether to file a motion to termination maintenance, the advice of an experienced lawyer is invaluable.