This is an interesting thread.
As much as I think Rumple is a coward, I don’t think that this situation is an example for that. He was going to leave Belle anyway – finding Bae is his life priority, he was looking for the boy for so long and now he is SO CLOSE. And he WAS trying to remind her of who she was but when he failed miserably, I think it occured to him that this will require a lot more work than he thought and that right now he cannot let those feelings cloud his judgement when looking for Bae. Together with Cora presenting him with a quick solution (the globe) to finding his son, it seems to me like he weighted the odds and decided to focus on the original plan and the quicker he goes, the sooner he comes back and only then he can properly focus on Belle’s case rather than rushing her into things. Plus she clearly needed some space.