Is this cheating?

Take his word for it UNLESS he has shown OTHER behaviors that make your feel that he has been cheating on you. He should tell you who is going on this trip and where they will be staying.

He may well be telling the truth. BUT, I cannot figure out how the single condom could have ended up in his suitcase. I mean, he bought a pack of condoms and brings them home the day before he packed (at least this is what you seem to say.) Then he packs, knowing you are not coming, but somehow "accidently" picks up the pack of condoms and throws them in the suitcase. Then he says, whoops, I don't need those. So he takes the pack out of the suitcase and in the process a single condom falls back into the suitcase which he somehow fails to notice until you see it in his suitcase. Ok, I guess it could have happened that way, and as the previous responder said, unless there are other signs that he is or has not been faithful, you need to give him a break this time and trust him. But it does seem a bit fishy.

Some men (I believe) like to jerk off into a condom, in order to reduce spillage.

In Newcastle they call that a posh wank.

Trust lost? Sounds like he is tetering on you losing trust in his actions and words. Be honest with your feelings and watch his reactions. Defensivness may be a sign of guilt. He may not have cheated, but maybe he is looking for a one time thrill elsewhere.

One condom is causing angst?

Haven't you ever found a random pen or tampon or pretzel or kleenex or lipstick or whatever in a bag/satchel/purse?

I'd probably laugh if I found one condom in a partner's luggage. I'd wonder why he wasn't being more optimistic. If someone's planning/hoping to cheat, one condom isn't going to be any use.

Is one condom in luggage cheating?

No.

No, it's not cheating, but I agree that his explanation is incredible. Having said this, anything can happen, and he could have been tossing a number of things from the pharmacy bag into his suitcase and he didn't noticed he also tossed the condoms into the luggage until he saw them.

Of course this wouldn't explain how one happened to have remained in the luggage when he removed the others if they were in a box, and since your sex life is "normal" and he has been more interested than usual, it seems like he would be buying a box rather than several individually wrapped ones.

In addition, if he did buy them as separates, it undermines the theory that he thought they were something else when he emptied the pharmacy bag. That is unless he also bought individually wrapped Alka-Seltzer tablets, or vitamin supplements...you should have an idea if this is his shopping habit.

I also agree that unless there are other reasons to suspect he is or wants to cheat on you (simply because he many have intentionally brought a condom with him doesn't mean he had an assignation planned), I suggest you not obsess about it.

Not to fan the flame of paranoia but I have heard that men who are having affairs often have more sex with their partners than before, out of guilt or an attempt to somehow through the partner off the track. Most people are not expert deceivers. If he's having an affair he probably has or will provide you with other evidence. It's up to you whether you care to look for it, or let it all slide. Ignorance can be bliss.

I'm assuming that your husband uses condoms in your normal sex life. If not you've found the smoking gun.