Will incorporating anal mean that he won't want ordinary making love anymore? Has it done that for you?

Will incorporating anal sex mean that he won't want vaginal sex anymore? Has it done that for you? Has it happened to your relationship?

My boyfriend/fiance and I have been together 6 years and we have plans to be married in the next few. We have been sexually active for around 4 and each other's firsts. We have a wonderful sex life, and I am open to trying pretty much everything except for bringing someone else in and anal. We've tried plenty of kinky stuff and we've only had vaginal and oral sex, however, he has expressed interest in anal sex. I am terrified that if we try it, and incorporate it into our sex life (once in a while) he will only want anal sex and won't want vaginal sex anymore.  Has this happened in your relationship? Anyone have experiences like this?

We have tried it a few times and it was either painful or emotionally repulsive to me. It's stuck in my mind that he only wants this because of porn (can someone please tell me I am wrong). I am terrified of the added feelings of inaequacy if he were to prefer, or only want anal sex to vaginal sex in the future if I were to agree to try it every now and again. I want to be able to give him everything he wants, but I cannot bear the thought of his possible preference of anal sex over vaginal sex.