Short and tall are relative terms to where you're located and what your heritage is. Many Asians tend to be a few inches shorter. The avg. North American male over 21 is about 5ft 9.5 in to 5ft 10 in according to statistics. So, 5 ft 7 in is slightly below the average. How meaningful is that, though?
That being said, many younger (and older) people don't sit down to a full balanced meal. Rush, rush rush! Likewise, they also don't get good regular exercise. Assuming you've had good medical checkups and got normal results, you could benefit from eating a balanced diet and good exercise. If you haven't had a recent medical checkup, then get one.
I was 5ft 7.5 in my teens and 20s and was 147-150 lbs for most of that time. According to most typical health charts, my weight was about right. At 5ft 7in, you could use about 20 lbs, unless your bone structure is small. If you have small bones, then perhaps 10-15 lbs might make you FEEL better and look better. That being said, cosmetic (surface) isn't what should matter much to you. Clearly you're bothetred by this issue, though.
What really matters most here is your self-esteem ...your confidence - not what is written on some health chart. Tell you wife you need her support, not her telling you that you're scrawny.
When contributing to an online forum be prepared to get answers you might not agree with or even like. However, the majority of times you'll get answers that are a good guide and helpful. Also, take the time to read the answers and grasp what is being said.