Jokes on you, you don't have to deal with anything. There's nothing for you to deal with. There is no problem or battle you're facing. Here is the wonderful thing about your friend being gay, it's not about you. It has nothing to do with you. It's about them. It's their life. The only way you should be affected by this information is by feeling assured that your friend is finally comfortable with who they are.
The biggest problem with homosexuality has nothing to do with homosexuals. It's the heterosexual people who refuse to accept that being gay is not a contagious disease. You won't become gay if you ride in the car with someone who is gay. Your relationship with your God will not be damaged by the fact that you have befriended a gay person. Stop playing God and let people live their lives.
Pretending like you are affected by the fact that someone in your life is gay is extremely self-centered. The reality is that it doesn't affect you in any way, shape, or form. You don't have to "handle" anything. The only thing you have to do now is to support your friend. Thanks to other closed-minded people, life may be hard for them sometimes. So be there for them when the rest of the world turns away. Love them. Love who they are. Love that they are happy. The reality of someone else's sexuality is that it's not about you. So quit pretending like it makes your life any harder because it actually makes life beautiful and diverse.