I can understand not wanting to "change the relationship", but they're already pretty intimate with each other. They clearly do have feelings for each other, as is demonstrated in later chapters too, but there really isn't a necessity to hold back anymore as anything that they do would not add or detract from what they do already. It's like watching an engaged couple who are forcing themselves to wait till their wedding night... admirable, but unneeded since the commitment appears to already be there.