common law marriage

First of all, are you sure that you are common law married? CO allows for this but certain requirment must be met, merely living tgether is not enough. Here is a link to a site that will explain further: https://coag.gov/resources/frequently-asked-questions/colorado-office-attorney-general-frequently-asked-questions. If you have formed a common law relationship, then the house is still considered to be the "joint marital residence". this means that without a legal separatoion agreement or final decree of divorce that states otherwise, you are both entitled to remain and live in the premises, no matter whose name is on the lease.
If you are not married and are not on the lease, then the situation is different. If you paid rent you might be considered to be your boyfriend's unofficial "sub-tenant" with him as the "sub-landlord"). Under this scenario, he can file an unlawful detainer action (i.e. eviction proceeding). However, this means that he will have to comply with all legal requirements in order to get you removed. This starts with giving your written notice to vacate. If you remain, he will then need to file suit in court for an "unlawful detainer" (i.e. eviction). That all having been said, If you are considered to be a "tenant", the only way to have you legally removed from the premises is to have the landlord (the owner of the property - his friend) file for the unlawful detainer action as a tenant can only be removed by their landlord. Further, having your name on a lease is not the only way that you establish a legal tenancy. In addition to being on the lease, you may have achieved the status of a being a formal tenant if his friend accepted rent from you directly. Also, if his friend put (or allowed you to put ) your name on the mailbox/doorbell, and/or if you and your boyfriend appeared together when he rented the house and it was made clear that you would be living there with him and would both be on equal footing as residents.

First of all, are you sure that you are common law married? CO allows for this but certain requirment must be met, merely living tgether is not enough. Here is a link to a site that will explain further: https://coag.gov/resources/frequently-asked-questions/colorado-office-attorney-general-frequently-asked-questions. If you have formed a common law relationship, then the house is still considered to be the "joint marital residence". this means that without a legal separatoion agreement or final decree of divorce that states otherwise, you are both entitled to remain and live in the premises, no matter whose name is on the lease.
If you are not married and are not on the lease, then the situation is different. If you paid rent you might be considered to be your boyfriend's unofficial "sub-tenant" with him as the "sub-landlord"). Under this scenario, he can file an unlawful detainer action (i.e. eviction proceeding). However, this means that he will have to comply with all legal requirements in order to get you removed. This starts with giving your written notice to vacate. If you remain, he will then need to file suit in court for an "unlawful detainer" (i.e. eviction). That all having been said, If you are considered to be a "tenant", the only way to have you legally removed from the premises is to have the landlord (the owner of the property - his friend) file for the unlawful detainer action as a tenant can only be removed by their landlord. Further, having your name on a lease is not the only way that you establish a legal tenancy. In addition to being on the lease, you may have achieved the status of a being a formal tenant if his friend accepted rent from you directly. Also, if his friend put (or allowed you to put ) your name on the mailbox/doorbell, and/or if you and your boyfriend appeared together when he rented the house and it was made clear that you would be living there with him and would both be on equal footing as residents.