Hi Rachel
To answer your question. It is possible for a guy to like 2 girls. Even 3 girls, even 4 girls, even 10 girls, even 100 girls all at the same time.
Find out what your situation with him is. If you are just friends then stay as just friends and see where that thing with him and the other girl goes. If he tells you that you and him are more than friends then find out what he is going to do about forgetting the other girl.
Quite simple really
Don't cry, don't regret and don't blame
Weak find the whip, willing find freedom
Towards the sun, carry your name
In warm hands you are given
Ask the wind for the way
Uncertainty's gone, your path will unravel
Accept all as it is and do not blame
God or the Devil
~Born to Live - Mavrik~