Friendships with others besides your spouse are a very good thing!
If you'll notice, the Bible stresses fellowship among church members, and there's a very good reason for that. Human beings are social creatures. We thrive when we're around others who share views (and sometimes disagree), who help us when we're down, and to whom we can minister and be ministered to.
I can see where you're coming from in thinking that your husband should be your only friend, but as Orchard says, it's unhealthy. Sooner or later, the marriage is going to hit a rough patch, or you're going to have questions that your husband cannot answer. Then, friends become invaluable.
If you need a "practice shot" on being open, then PRAY. Seeing as He created us, God knows our hearts and our minds. I don't know about you, but I had an extremely hard time at first opening up to anyone. It was the legacy of years of emotional abuse, but I still couldn't quite comprehend that I could dare to open to someone else. Thus, my prayers started changing. Instead of dry prayers, I started opening up my deepest, darkest secrets to God. After all, He already knows them, right? It was liberating to pour my heart out to Him, to bring to His feet the hopes, dreams, thoughts and pain of this tortured soul. It was only when I could bring everything, even my anger, to God, that I felt I could open to someone else. And it was blessed!
Making friends isn't hard, you just be yourself and contribute to a conversation. When I started at hubby's church right before we were married, I didn't know anyone. For a while, I kept to myself. Then, slowly, I started small-talking before and after services, and God blessed that effort with two very good friends. Before I knew it, in three years God blessed me with many friends in that church. You already have something in common with others in your church (a love of God), so take it from there!
Another way to socialize is to join in on whatever little classes your church offers. Small home groups are awesome in the way that the meetings are informal, and you get an opportunity to know one another better. Married couples' classes, or fundraisers, will also get you in a position to meet others. I've even made one or two very good friends while ministering!
Don't sweat being scared of meeting new people. I was extremely introverted, and totally dysfunctional in regards to friendships, when I started making friends in church. It just takes being open, prayer to God to bless your efforts, and sharing life experiences, and sharing laughter.