I really don't know how to put this...

I have a wonderful husband, 27, married a little more than a year. He's smart, ambitious, a hard worker, and absolutely lovely to me. And he has more (women's) yoga clothing than I do, and that's saying something. I don't have a problem with it, I simply don't know what to make of it and am worried it's a sign of a larger issue/want he's too embarrassed to share.

He started wearing them on a camping trip when things got colder than we expected, he only had shorts, and I insisted he wear mine. He mentioned he loved the way they squeezed him when he slept, so I suggested he should get some to wear to bed. One year later, now he's got 20 pairs of them along with a heap of yoga tanks, which he wears all the time at home. I'm okay with this. It's certainly not what I expected, but he's a wonderful husband and a dream in nearly every way (and he does have a cute butt). I've tried to draw him out as to whether this is a smaller part of some sort of much bigger unfulfilled need, and he swears up and down that it's just that he finds the squeeze of the clothes calming and comforting (and he does tend to buy either heavyweight clothes, often with powermesh).

I'm no longer sure I totally buy this. Having done some snooping into his browser history, which is usually meticulously clean, I recently found a visit to a transgender(?) fiction website with stories of men "forced" to be women. I'm at a loss to understand what's going on inside of him, but feel like there's this enormous chasm between us. Some integral or essential part of him that he cannot and will not share with me for whatever reason. It pains me that he won't share more, and even more it pains me to think that he feels he can't be himself with me. While, let's be honest, I need him to be the man I thought I was marrying sometimes, I have no problem with him going around the house some of the time, or even most of the time dressed and looking as he chooses if that means he gets to be himself in our relationship and stays the same wonderful partner. I'm of course terrified that this opens a wormhole to him wishing to live as a woman full-time, which I can't see working for me. But I cannot bear the idea of him having some sort of (to him) shameful secret inner life that's totally kept fully from me indefinitely. At the very least I need honesty.

I have no idea how to draw him out into being open (assuming he's not), given I've tried so many times. I don't know whether to bring up his web history, which shows him I don't trust him and would (is?) some sort of betrayal. I've thought about simply suggesting/inviting him to wear non-athletic women's wear and see if he bites - maybe starting with spanx/shapewear or "control" clothing, which would let him keep to the safety his cover story. It's almost Halloween, which is maybe a good opportunity to draw him out? I'm worried that if I just let him "come to me" I'll be waiting for the truth forever.

I feel misled about who is (perhaps) is before we got married, and though I'm not bitter about it, and I don't even mind him being a girlfriend or wife sometimes, it's a huge relationship red-flag to me. I just need to know where I (and he) stand so I can have some clarity about my future. Help!!! Ideas?!?