How do I evict a live in boyfriend?

There are few options, but make sure you really own the place.

Tell him nicely.
Tell him you're moving out and planning to live somewhere.
Annoy him
If he doesn't want to leave, serve a "notice of eviction" and have police help you.

Do you rent? Is he on the lease? If so, how many months left on the lease?

There are allot of things we need to know before we can give you advice.

Also is this registered domestic relationship ( in a area that has these)
Since he may have a right to be there though that.

Is his name on the lease ? If she it may not be possible to evict him