Glad to finally see some other people noticing the worrying behaviour from Nate. Kinda baffled that he's seen by a lot in this thread as 'Mr Perfect'. Don't get me wrong, to begin with I thought the same...when he lends her his car, helps her out with the nursery and offers to let her stay but that soon changed when it becomes obvious his kindness and help comes with a sense of entitlement that he'll get something out of it.
I think what we're meant to see in Nate is that controlling behaviour comes in several variations, even in the form of the purported "nice guy".
When the offer of a helping hand comes bundled with immediate and repeated pressure to jump into a relationship, when the guy knows full well she was just traumatised, is actually not that helpful.
In the end, we see Nate's offer of help was indeed conditional.
She told him repeatedly that she wasn't interested, and he said that was ok, that he still wanted to help her even if she didn't want to be with him romantically, and then he took it all back once he saw she really did mean it. That's manipulative and dishonest. It would have been more honest if he'd just said "you can stay at my house as long as you have sex with me and no one else." At least then the terms would have been clear. She did not owe him monogamy.
A truly nice guy wouldn't have made a toddler homeless again because he got his feelings hurt.