Yes, I feel a little guilt and regret after I cum, also some jealousy. That's why whenever my wife lets me watch, I'll masturbate but try not to cum. Most of the time when she's done she'll let me have sloppy seconds so I get to release then. I will say that even though I know I might feel bad afterwards, the times I do cum while she's fucking are out of this world fantastic. On some rare occasions she'll suck my cock while her lover fucks her to orgasm. I cum incredibly hard then. Those times I don't feel bad. I guess because I was a part of it.