@bubsy83,
Let's just start with the 'effeminate walk' is just bullshit and it's mighty offensive and just plain wrong. There are Marines who are gay. I scarcely think they engage in this so-called 'effeminate walk' you have decided is a clue.
A far bigger clue is the texting and the messages and the clear persistence he's engaging in with other men. He's asking other men out on dates?
How obvious does it have to get?
He is likely already having sex outside your marriage, and this is probably just the tip of the iceberg that you've found. You don't seem to have children and you, personally, don't sound at all happy. And nobody's talking about love.
So - cultural stuff aside -
why stay married?
Was this an arranged marriage? Surely there are ways to end even arranged marriages, as there are major incompatibility issues. I take it that it would harm your husband in your society or perhaps in business if he were to come out. But the truth is, he's using you for a beard and is not being fair. You don't sound terribly interested in sex, anyway, but who knows what would happen if you had a chance to have a different partner?
Hence my suggestion is to sit down and talk, calmly and rationally. This is not the time for accusations. And it isn't time for questions, either. The guy didn't join Adam2Adam for fun; he joined in order to hook up with guys.
Tell him that you know that he's gay. This is not you asking, so that he can deny it. You're telling him that you know. No crap about the walk or how he dresses, for God's sake. Let the guy have a little dignity. And tell him, this marriage isn't working out. We are both unhappy. I (meaning you, of course) am young enough that I could have children if I wanted them, but that's highly unlikely in the current circumstances. And talk about how to fairly and maturely end your marriage, so that everyone saves face.
There has got to be some way or another to do this, as I bet you're not the only wife who's been in this particular predicament. But do be kind. I bet he's scared and nervous about pretty much every aspect of this. Let him know that you can be a friend in this area and you can help him, but the price for that is him letting you go so that you can have a life without him as your husband.
Best of luck to you both.