This is a fairly normal feeling, especially if you define yourself as a man in your daily life. Sissification tests your male ego and it is a very common fantasy for men.
In a nutshell, you have 2 options
1) Learn to love yourself. Realize sissification is simply something that makes you happy, but it's not something that completely defines you. Sissy porn makes you happy and this doesn't make you any less of a man in a normal situation.
2) Stop. You will not have to struggle with your doubts. However, it will take away the happy part. Quite an unhealthy option in my mind.