Do you think he's going to propose?? And is it appropriate to say yes?

He's been sending me pictures of rings, asking my opinions, he's planned a trip to the Florida Keys, and he's been super attached the past month! Plus I saw a thing on his bank statement where it looks like he's making payments on something... I didn't look into it. I love him so much, and we've been together for over a year now! But his divorce isn't finalized yet... I really want to say yes (if he is proposing) but I don't know if it's appropriate to say yes while he's still legally married. Any opinions?