We do the same I love hearing my mates making her cum, and I love watching her be the dirtiest kinkiest sluttiest fuck they ever get. Almost all my mates have fucked her, some have fucked her many many times over the years. I watched this with my wife - she told me there are at least 3 guys at work that she would be willing to try this with.
Encourage lovers to focus on their pleasure. Some people who take a long time get distracted from orgasm imagining how fatigued, bored, and annoyed their lovers must be. Encourage your lover to focus inward on experiencing pleasure-and not on fears of any negativity you might be feeling.