You realise that what you're saying here is that if you were in a situation living with your best friend on a year lease, got offered a job that doubles your salary 300 miles away, took the job, told your friend you had to move but found mutual friends to take your place which he/she refused, so you continued making payments keeping up your end of paying half the rent, continued to do so for a long period of time, find out that he/she actually found someone new to live with her/him who is living rent free in the house due to your continued payments, you would have absolutely zero problem with that and in fact would look at yourself as the asshole even though your paying someone else's rent?