story identification - Trying to identify novel with a man imbued with uncontrollable telepathy

I am trying to identify a fix-up novel, where I think I only remember a sub-story from the middle. It was probably published at least fifteen years ago, but I cannot pin down the date better than that.

The main character volunteers to travel to an alien world (maybe with the first intelligent aliens humans have identified?). A remote probe had sent back some visual data on the aliens, before the aliens destroyed the probe. The main character has some history as an amazing explorer or risk-taker, and he is sent to try to establish communication with the aliens. His chance of coming back alive is rated as being very low.

I don't think it's clear what happens to him on the aliens' planet. Maybe he doesn't remember it, or he thinks that his mission was a failure, and he eventually decides to return to Earth. However, upon his return, it turns out that the aliens have modified him, in an attempt to enable communication. He has become an overpowering telepathic projector; every thought and emotion in his mind is communicated to everyone near him. This is extremely unpleasant at close range. (I think there's a scene where his girlfriend is really, really trying to have sex with him after he comes back, but she is ultimately unable to.)

Eventually, he decides that he cannot live around people any more. I don't recall where he goes, although I think the last part of the book features people from Earth trying to get him back for another mission (perhaps one for which his uncontrollable telepathy might be useful).

Answer

'The Man in the Maze' by Robert Silverberg.

"During his heroic first encounter with an alien race, Dick Muller was permanently altered, hideously transformed in a way that left him repulsive to the entire human race. Alone and embittered, he exiled himself to Lemnos, an abandoned planet famed for its labyrinthine horrors, both real and imagined. But now, Earth trembles on the brink of extinction, threatened by another alien species, and only Muller can rescue the planet. Men must enter the murderous maze of Lemnos, find Muller, and convince him to return with them. But will the homeless alien, alone in the universe, risk his life to save his race, the race that has utterly rejected him"