From sources such as here the consensus seems to be that Candida Albicans is not an STI, but can be "passed back and forth" if engaging in intercourse with the same partner. So, why would this not affect say, a new partner?
Although Candida Albicans can be transmitted sexually, generally it is developed without sexual contact. WebMD gives the following details
Normally, a type of bacteria called Lactobacillus keeps the amount of Candida in the genital area under control. However, when Lactobacillus levels are disrupted in some way, Candida can overgrow and cause an infection.
You can also develop a Candida genital infection after participating in certain sexual activities, particularly those that involve oral-genital contact.
Although otherwise healthy individuals can get genital Candida infections, the following groups are at an increased risk:
- people that have taken antibiotics recently
- people with uncontrolled diabetes
- immunosuppressed individuals
- pregnant women
- people that are taking oral contraceptives or who are on hormone therapy