Cheating is a hot topic for me. As for taking the plunge, only you can really decide on that.
If it is something that excites you and you feel will satisfy the itch, test the waters and see what happens. I would love for my boyfriend to be fucked raw by an older male. We have fooled around a bit with a few others, but not much more than kissing and some sucking. To see him being fucked, would be the ultimate. Something raw and exciting about cheating, or seeing a partner get fucked, especially raw.
The ultimate for me would be to see my boyfriend being fucked, the top pulling off his t-shirt and see that glorious bio tatt! I would so have him pull out and rip off that condom and plunge his dick back into my boyfriend.
If you want to take the plunge, I encourage it!