OP, are you absolutely sure he's on the same page as you with regards to the future? I'm having trouble seeing a man who thinks expending time and resources on his gf is an inconvenience to his self-interest, wanting to become a husband and particularly a father - a role that basically requires the majority of both. Is there a possibility he's just gaslighting you with the 'future' plans, in the hope you don't notice nothing changes... or does he genuinely just need a kick up the ass to get started? I think you need to talk to him seriously about where his head on this - because as much as you don't want to 'nag' him into a proposal, you also need to know that it's going to happen because if it's not on his radar, then you need to get out and find someone who puts your interest equal with his own.

It's easy to keep an easy-going person happy with compliments and affection, but he also has to know how to commit... when the bad times come along, how convenient will he find it support you, or the children you have? Make sure he's the guy you want to move forward with.