From reading your posts I'm not sure of the tone in her voice when she makes these remarks. I can imagine that she's ribbing or teasing you, but it sounds more like she's really getting on your case.
Although we don't really know you, it appears that you aren't a manly type even when you aren't dressed en femme. So it's hard to say whether she found your stash, has suspicions based on something else (makeup residue etc.) or if she's just referring to your personality.
It also appears that she's just getting to know you since she didn't already know that you iron your cloths. How long have you been in this relationship? It certainly doesn't sound like you're happy living with her.