If you are referring to an adult sex toy as a doll and how it may affect a relationship:
You must ask your partner if they are actually comfortable with the idea of it. If they are comfortable with it, than there could be benefits to it, such as:
- you may want to have sex but your partner may not want to have sex, so having a sex toy doll may accommodate your needs and this often leads to not having the emotional attachment that comes with another human
- you may use the doll with your partner in mind and this will get you away from porn
Of course, there could be disadvantages too, including a person wanting to always have sex with the doll, a partner getting jealous of the doll, or anything else.
So if you are considering on introducing such a toy, you must delicately speak with your partner about the idea of bringing it into the bedroom, or even keeping it. Ensure your partner that you still love them and that you only want to bring in a sex toy doll as an alternative, as you have very horny needs and that as much as you would love to have sex with your partner every single time, they are not always in the mood, but it doesn’t mean that you aren’t in the mood, and this will help you to alleviate your own tensions.