There are two types of herpes (HSV), herpes simplex one and herpes simplex two. Both live in the spine in a latent stage, and are most likely to manifest themselves when someone is feeling depleted. simplex one generally manifests itself on the mouth as a cold-sore, and simplex two generally on the genitalia. however simplex one can appear on genitalia and vice versa. 

What you're more interested in though is transmission. Herpes is a skin to skin transmitted disease. Meaning just rubbing of the genitalia, closed mouth kissing, and oral sex can be modes of transmission. one of the most common ways of it spreading is parents kissing their children. Also, the most contagious time for the virus to spread is not during an outbreak, rather when the skin is "shedding". An outbreak may never actually occur.

Herpes can manifest itself in the nipples, usually from mouth to nipple contact, but as it is a skin to skin disease it is indeed plausible for penis to nipple contact to be a mode of transmission for the infection. one in four adults in the USA have herpes, and since the most common symptom is no symptom at all it is incredibly possible you're partner would be unaware of his condition if he was in fact infected. 

Tests are available for herpes which include a visual examination, a culture if there is a visible sore, or a blood test. I would look to a local woman's clinic or planned parenthood for cheapest pricing.