Need help identifying an old novel.

[Lord Anubis]

Need help identifying an old novel.

I read a sci-fi novel years ago, most likely sometime in the nineties, and I wanted to read it again. But for the life of me I cannot remember either the title or the author.

What I do remember about it is that Humanity had made contact with an alien race who offered to provide FTL engines for humanity. Humans weren't allowed to see the inner workings of the engines and that the aliens would have to run/operate the drives on all human ships. The kicker is the reveal that the FTL engines are in fact a space born creature that is slowly consuming all the people on-board the ships. Every now and then a ship would go missing since the creature would just insta-gib the crew during FTL.

Also the main character near or at the beginning of the novel is suffering from Ennui induced impotence caused from some field that the FTL engine gives off. The ship he's on is a traveling university space ship. That's all I remember.

Can anyone help?