My husband likes the idea of me meeting other men

2 months ago during a date night was more vocal than normal telling me he wanted to watch me with other men, I thought it was just playful during sex but the next day he told me he meant what he said, I was shocked as he had never said anything like this before, he let me know he had always fantasised about watching me having sex with other men. We spoke for a while about and I then said I needed time to think about this. I have been satisfied by my husband but he says he knows he's not very well endowed and wants me to have mind blowing sex, I tried making him understand I am happy with him but he kept saying he knew I would enjoy a larger man. He wanted me to know he loved me and only wants this as he wants me to experience the best sex as part of our relationship. I am confused about it but am considering going through with his fantasy. Am I wrong for considering this. Are there any risks to my marriage if I let this happen, please help me think things through