It could reduce shallow relationships that only serve to release some "pressure" and thus foster for more in-depth interactions with actual humans. That could reduce the amount of people that are immature in just about every aspect before throwing themselves into a marriage or having children, which could produce more balanced humans in the long run.
It could also potentially lead to people spending more time on picking up skills and hobbies as they won't be clogged up with superficial relationships that merely resulted from their sex drive.
Of course there's a shadow side as well, but it's not all as bleak as some people like to make it out to be.
I actually think that this is already happening.
Historically, women were dependent on men for their labor and men were dependent on women for sex. The resulting "power over" relationships often had problems with manipulation and bullying on both sides.
More recently, advancements in contraception, industrialization and pay equity for women has largely freed them from their historical dependence on men, skewing the power balance radically in their favor.
But, even more recently, the advent of ubiquitously available internet porn has largely freed men from their dependence on women for sex. I see the coming sex bots as merely a continuation of this trend.
The power relation is swinging back into balance, but in an entirely new way where neither gender is dependent on the other for their needs. For perhaps the first time in history we have the opportunity to form mature, discretionary and fully consensual relationships not based on fear.
Men, meanwhile, have historically failed more than succeeded. Only 40% of our male ancestors reproduced. It doesn't bother us nearly as much, and an expensive masturbatory aid makes at least a semi-serviceable substitute.