What are the chances of contracting an std when there was no fluid transfer?

HSV1 or HSV2 can be contracted through genital to genital, mouth to genital, or mouth to mouth contact (no fluid needed). Crabs and HPV can be contracted without fluid too

A lack of fluid transfer reduces the potential for STI transmission, though it doesn’t eliminate it (any bodily fluid, including saliva, to any mucous membrane, including mouth). Usually, the biggest concerns in the absence of fluid transfer would be HSV or HPV. For most individuals, if they were to have contracted a disease from something 4 years ago, they would have shown some sort of symptom by now.

Why not just get tested? It’s the only surefire way to know, and it would probably ease your mind.