I cannot say that I kept a secret from my wife. When we married we did not have a stitch of personal belongings because we were both in the military. I never had any female garments. My cross dressing had been limited as a teenager to using my mother's garments. When I married cross dressing was so far removed from me I thought it would never return. It returned with lingerie for "bedroom play." My wife participated. It was never a solo activity. However, I did start exploring my interest with slips and panties. Buying a Vanity Fair red bra flipped my wife from participating to DADT. So, is it a secret when she has knowledge of my cross dressing, but, sticks her head in the ground. I do not intentionally leave any vestige of my dressing out for her to see. She has no idea of the amount of clothing I have amassed. She has knowledge, but, no interest, so I do not consider it a secret. She knows I collect stamps and coins, but, has absolutely no interest in those hobbies either.
My suggestion is to tell her your "urges" are returning. And, you would like to explore those urges. See what she thinks. If she says she is OK with cross dressing, I would not pull out your finery and show her. I would acquire new items. It may be deceitful, but, I feel it is better than doing a reveal, and, then tell her you've been doing it behind her back. If she says she will not tolerate any interests in cross dressing.... well, the entire issue may blow up in your face.
Before I married my wife of forty plus years, she told me her past. She did not keep it a "secret," although I would never had asked her to reveal any of it. I really thought about her revelations, and, I still took the plunge. It has been tough sometimes... many times because of her past. The issues that have arisen over the years because of her past greatly outweighs anything my cross dressing has brought about.