If you restrict yourself to a strictly sexual interaction then i guess it will get boring quickly , sex only keeps us interested up to a point , if you want a girl to completely monopolise your interest and make you lose interest in seeing other women maybe you need to try and find a girl who engages you not only sexually but also on a personal level, psycologically and sympathetically on a human to human basis , Aka try an emotional attachment , much disapproved of on here obviously , but so long as you keep your head on straight and you actually find a nice honest girl emotional attachment can be next level punting, if thats what your looking for , which it sounds like it is.