No, you might have other reasons to question her fidelity that you don't mention here, but a rash on your penis and small cuts on your foreskin wouldn't come from condom use of someone else.
One woman wrote in on this site that she had been told by her boyfriend that her vagina felt rough, and she discovered that she had genital warts. Men get rashes on their penis from other things besides their wife. Your wife could have shaved and let it grow out as stubble. All kinds of things can bother and abrade the skin of a penis, but a condom is not one of them.
Infidelity is not suggested by the symptoms you have named here. Sex with someone who earlier had sex with someone who wore a condom is not going to give you skin abrasions
John I think the phone issue is smoking gun that the majority of us learn about affairs from. Your gut telling you something is going on is something you should listen to. Your possibly dealing with an inability to believe she could do this to you but for a variety of reasons it happens a lot. And the number of wives cheating has gone way up. Many people will want to tell you what to do and in my experience it was all tracking and recording gadgets and a divorce lawyer. And if you don't follow. The people who "insist" this are (my opinion) real ******** who make an awful thing worse.
My experience was that I didn't discuss this with anyone but professionals. Therapists for one. It hit me very hard so I also had to speak to my family Doctor about it and was put on some meds (Which I urge you not to get freaked out about) I said something about this and was informed that more then half the people working there took them due to stress. And whats more stress filled then dealing with infidelity. I also want to urge you to get tested for STDs, HIV and whatever else your doctor thinks is needed. In my case I got it into my head that the affair was due to me not being enough or wasn't kind enough or (fill in the blank)
Its very important to know that a marriage is not an automatic divorce. If you think your wife is having an affair I would read "Not Just friends" by ???? Glass. If she agrees to work this out couples therapy is a huge thing. I call it "Adult Supervision" because you can have a better talk with someone there to keeo things from going overboard. There is one other book titled something along the lines "How to help your spouse recover from your affair. Its meant for her to read and spells out some must haves if there is going to be a chance to solve it.
There is a group in most major cities called BAN. Beyond Arrairs Network. You meet once a month with people who have been betrayed which is easier to talk to because while affairs are sadly very common people who admit these and want to talk aren't. BAN once a year has a weeked retreat thing that we are trying coming up soon in Minneapolis.
i don't know if your wife had an affair but if she did she is giving you the type of responses that I've heard from other BAN members. Its very difficult for most of us to believe they could do this. And we want to believe them when they say they are not cheating but as in my case my wife told me "you could be really clueless" Which I would like to say was wrong. I had plenty of concern but I gave her the benefit of the doubt and took it as some sort of personal failing that was causing her to do this. Trusting someone is great but there are lots of temptations and we are not perfect. Stay frosty - don't be afraid to talk to a doc and without being too obnoxious about it keep your eyes open for clues. Those web sites she is on scream bad news but... There is a lot of disturbing crap on the web and sometimes its like driving by a car crash. You just have to look.
I don't know if she is sleeping with her ex, but have you had a doctor look at your rashes and small cuts? You really should. This could be something like balanitis, and if it's not going away, you may need treatment for it.
It's not caused by an STD, or even from having sex.
The question here that you seem to be asking is if having a rash on your penis means your wife cheated on you. I'd say that this is a leap and as auntiejessi and others have said, that in no way means she has cheated on you. If you don't trust your wife, that is a problem for he relationship.
You are looking on her phone. Why? How is your relationship in general? How do you get along? Do you have intimacy (emotional or sexual)? Those are bigger questions. Just talking to an ex does not equate to an affair in an absolute way. But no, I wouldn't like that either.
I would continue to go with your gut. As far as her phone and things like facebook Trusting your wife is very noble but... if you have seen these types of things on her phone it would be pretty dense to ignore the signs. These two things are maybe the most common clues of infidelity. If your wife has problems sharing the passwords on her accounts and phone it might be worth while to ponder why this would be a problem. I hope that she is not cheating and that you don't have a STD. Either way take care of yourself and don't be afraid to talk to someone who is an expert. And probably not get too much info from the internet. *And I include myself.