It’s crazy, but because the focus for Dan and Amy has been so much on the pregnancy, I’ve forgotten about the fact that they’re forced to address that they slept together. It seems like they were probably keen to avoid it but then Amy wound up pregnant.
The more I thought about it, the more clear it is that them sleeping together meant something, which is why they wanted to avoid it. Unlike 5×02, they weren’t conveniently outside a hotel room, they actively left a bar together.
And the most telling thing is that Amy is not generally a physical person and we’ve only seen/heard of her sleeping with people she was in relationships with, yet she had a one night stand with Dan. Then Dan uncharacteristically didn’t seem to tell anyone or tease her about it like he has with every other woman he’s hooked up with throughout the show.
The baby is almost just a physical reminder that he slept with someone he actually cares about, and not for status, power, bragging rights, etc. Which makes sense of why he starts to have “an identity crisis” and realizes maybe he wants more than to have sex with random women.
Of course, Dan did react to the one night stand with Amy, because the next interaction we see is Amy meeting with BKD to talk about a possible job. I find it hard to believe Dan wanted her to come work with him again for purely professional reasons.