Fair enough, but it wouldn't need god-level intelligence to be bored. If it even came up to the intelligence of a regular person, wouldn't it still want something out of a relationship? Or is the point not to simulate human intelligence but rather the personality of a lobotomized person, with their desires, complexity, and individuality removed/limited? Does OP just want a semi-autonomous cuddle-bot? If so, we may be getting to the core of why OP is disillusioned with human relationships.

You seen the movie Ex Machina? Humans can have high standards, be needy, volatile, etc., But what makes you think a sentient AI partner would be different? Would it not expect you to bring something to the table, or change its mind about things down the road? The movie Her is also pertinent here because by the end of the movie, the AIs basically become so advanced that humans offer them nothing. You may want to ask yourself why a robo gf would want you, assuming they have a choice in the matter. Or are you thinking more of a subservient robot that isn't truly sentient?

Not trying to be derisive, I think this is a very interesting topic. I think talking through some of these questions may actually help you with your own personal journey with human relationships; relationships that don't start with you purchasing a partner.