Cavilon skin protectant by 3M is a favorite of many ostomates. It is available on Amazon and through any ostomy medical supply company (Edgepark, Byram). Cavilon is a favorite of most individuals with an ileostomy. It comes available as both a spray and as individual towelettes. I prefer the Cavilon spray.
If your parastomal skin is excoriated and weepy, there is nothing better than Marathon Liquid Skin Protectant. Marathon Liquid Skin Protectant is an advanced wound care product specially designed to treat skin damaged by exposure to urine/feces. Marathon is like super-charged Cavilon. Its skin healing properties are nothing short of amazing. Marathon is available on Amazon without a prescription and through ostomy product suppliers as a wound care product. Marathon Liquid Skin Protectant is somewhat expensive ($65 for 5 one-ounce vials) but well worth the cost. I always keep a few vials available for unexpected skin breakdown.
You can also use a bit of NeoSporin (as your girlfriend has suggested). You would then place a protective cover of TegaDerm or Duoderm (the clear adaptic dressing placed over IV sites) over the NeoSporin and your ostomy wafer placed in top of the TegaDerm/Duoderm.
The United Ostomy Association of America (UOAA) has a nice support forum as well as informational PDFs on a wide range of ostomy topics that you can read and download for free. Topics include skin care, hernias, food/diet choices, intimacy, etc. The UOAA also offers a quarterly magazine called The Phoenix that is a valuable resource for both people new to an ostomy and to seasoned veterans. There is a good depth of knowledge in the members of the UOAA support forum.
For undergarments and light compression to minimize risk of a hernia I recommend ComFizz, a small company in England. ComFizz makes undergarments (t shirts, camisoles, boy shorts, briefs) designed specifically for individuals with an ostomy. They also make innovative belly bands and stoma guards. ComFizz has been received several awards by the British NIH health system for its quality and innovation. Ordering is simple and shipping arrives via US mail in about 2 weeks. There is a toll free number and e-mail chat feature to connect with a customer agent to help with sizing decisions. I have worn ComFizz garments for the last 6 years and am a loyal customer. There is simply nothing better.
I don't have a problem with my skin...the irritation is on the stoma (intestine) itself.