It is not selfish. However, it is not a very smart decision for your own future. For example, being a homemaker (my grandma was one, never worked a day in her life, had to marry man after man who was sometimes abusive and couldn't leave him if she wanted to) makes you almost like a prisoner. After a few years of being a homemaker, you have a big gap in your resume if you ever want or need to return to work.
What happens if your husband unexpectedly dies? What happens if he cheats on you or you two get divorced? Do you have your own savings to take care of yourself so that you don't end up homeless when s*** hits the fan? What about your retirement savings? How are you going to take care of yourself if you're at the retirement age and you don't have any savings or pension and your husband passes away before you?
I also wanted to be a homemaker for awhile, but then I realized it's just too risky.
After watching my sister be a homemaker for five years, with a four year old daughter, her husband who was a marine cheated on her with multiple women and left her. He barely sees his daughter and refuses to help my sister with the bills. So now, after five blissful years of being a homemaker, she is deeply struggling to stay afloat as a single mother.
After searching for a job for many months she finally landed a job as a bartender, and she's constantly tired.
No its not selfish to be a homemaker, but it's not smart.

Edit - By the way, if you're thinking "Oh he would never cheat on me." You never know what the future will bring. My sister never imagined her husband would cheat on her (let alone with multiple women). Accidents also happen, diseases happen, any number of things can go wrong. That's why it is soo important to have your own form of income - not just for your own retirement, but for your peace of mind too. If he is telling you he doesn't want you to be a homemaker, but you do it anyway, he very well might end up resenting you and leaving you. It happens all the time to women. It would be different if he said, "Sure honey, that sounds great, I'll take care of us." and even that would be risky, but he's being honest when he expresses how he feels about it, so if I were you, I would listen to him - because if you don't, then yeah it might be selfish.