Just wanted to update that I had my son. No DNA test was needed. He looks just like my husband and our first son. They’re all 3 identical.
Another edit is that the discharge part was with guy A not guy B. I was in rush typing my apologizes.
Certainly the first guy has much worse odds. They aren't zero because pulling out is not infallible, and asking a guy when he last ejaculated isn't infallible either (he could have had an ejaculation in his sleep the night before the sex and not woken up). But the first guy is 4 days before the presumed ovulation (not early enough to be certain all possible sperm is dead, but it suggests that all sperm might have become nonviable by then) and he did pull out. Whereas, another guy ejaculated four different times in the exact right time frame without withdrawing. He sounds like the most likely dad. Have you considered getting a prenatal DNA test done with both guys? It would put any question to rest immediately.
To add, I do not have the funds for a paternity test. Guy A fully believes it’s not his and Guy B believes it is his.