Huh. I can really see that going either way. If she had a previous relationship where the guy got mad if she had male friends, even if they were platonic, I can see that she would really be uncomfortable about telling you (even though she totally, totally should have), even if there was no hanky-panky.
Underwear doesn't necessarily mean anything. We wimmins DO buy underwear now and then.
Clothes, too.
But it could all add up, yeah.
What are your plans, if any?