If you have roughly the same rating both of you should be gaining the same amount on a win. However many rating systems have some kind of aging factor. Meaning

If you have roughly the same rating both of you should be gaining the same amount on a win. However many rating systems have some kind of aging factor. Meaning the more games you play the more stable your rating gets. So it could be that your opponent has played significantly less games than you. However if he loses he also should lose more points than you would. The color you play has no influence on the rating numbers. And also the type of win/draw/loss does not matter at all. Ratings are just statistics of your results.