If you are ashamed of your problem, you will be ashamed of the cure. Shame is not what you want to bring with you back home for the holidays. Tell others that you are going to ManAlive or working on purity; don't let shame keep you locked up. Find a few people you can share intimately with. Maybe not to everybody and don't overshare too much, but definitely push the boundaries of what feels safe.
You sharing is also a prophesy of Jesus setting you free. If you are part of ManAlive, you are not the same passive man hiding in shame that they once knew. If you've been coming to small group, you have changed and our changing. Even when it's hard and you stumble you are still doing something bold. Be proud of this. Be confident in the new you. Share to get you better and share to get them better.
Don't bury the gift you've paid for week after week, share it.