Sammie,
The competition you mention can take many forms, and it's not always about height/weight proportions. The clothes you choose can also contribute to conflict if she feels you are dressing with a higher sexual "temperature" than she is comfortable with.
My SO was somewhat critical when I came out in skirts shorter than hers and in back-seam stockings. The very clothes that made me feel feminine were in "competition" with her usual dress. Larger breasts, redder lips, and higher heels all work to make some SO's feel like they aren't enough women for us.
It is a very hard thing to work out, and I truly envy the contributors to this forum that have SO's that support them. You have my best wishes that it works out for both of you.
