I suppose everyone is assuming there is something wrong with being reserved. I don't think there is. If you, however, believe this is something you'd like to change, by all means seek professional assistance in helping you do so. Otherwise, embrace who you are ;)
There's nothing wrong with being reserved. I'm an extremely introverted person myself. There's a big difference, however, between being reserved and being unable to show emotion to and communicate with the person you're married to. The latter is not conducive to a healthy relationship. Obviously, the OP feels this is having a negative impact on her life and therapy can be very helpful in this area.