"Soft" DADT can work in my opinion, depending on what you're looking for. My boyfriend and I operate with this kind of relationship. We haven't met each other's spouses, even though we've been dating for over 2 years. And we dont tell our spouses details of our dates. But, I do let my spouse know when I'm seeing my boyfriend and some things about him, like random stuff like, "boyfriend liked X movie," if husband is wondering whether a movie is good. And we have been to each others houses, when our spouses were out of town. Strict DADT seems impossible to enforce, unless one is cheating, like you said. I think someone who is DADT, but shares details of their life with you, is usually OK, in my experience. But if you dont know enough details to find them online, they are probably cheating.