To start with, marriage is a sacred bond between a man and a woman, so if there should be a third person in your relationship should be God. Dont understand the idea of a threesomes in the first instant.
Second, your marriage is too young for you to be loosing interest. The moment you said 'I do' you swore to be content with what your marriage gift box had to offer.
Your post didnt reveal you were forced into the marriage, you saw your husband for who he was and chose to accept him. His looks didn't change, you accepted him then, and you should now.
What you need is to rekindle the flame that once glowed. Review what attracted you guys and bring those special moments back to life.
Discuss your concerns with your husband, make the needed sacrifice and changes. Put God first, and I can assure you there will be great improvements.
Ultimately, learn to be content!
Not many are aware of the fact that every sexual interaction between two people is a foursome!
Two humans, accompanied by their two god-selves.