If you only stay in for the sake of others, then they are using you.
If they would throw away your friendship in a flash because you were not a member, then they are not really your friend.
It comes down to emotional blackmail. Would you stay someone's friend if they made you pay them $20 a day to be a friend with you? Essentially that is what is happening, except the price you are paying is your integrity. Constanly living a lie can have major toll on you.
You very well might be fine with this, and I'm in no position to judge. But you would be good to ask yourself why are the opinions of friends and family so important to you if they don't feel the same way about you?
For me, I stayed in as long as I did because my wife didn't have major issue with me fading. If we didn't have children, I could see me still being a member. I couldn't raise a child in the religion though, forcing them to live a lie and put up with riddicule and abuse wasn't an option when I didn't believe the reasoning behind it.