HE FLIPPED OUT!!🤦🏼‍♀️‼️ Advise?

I was hanging out with my sister the other day and I had my 4 year old son and she was getting rid of her daughters clothes that she had just grown out of and my son looked interested in the clothes that we were picking through on the bed and he ask why his cousins got to wear bows and dresses and he couldn’t so I told him that he can wear whatever he wants to wear just like if his cousins want to wear cowboy boots they can. I let him try on a dress and he put one of the little headband bows on and I took a picture of him so he could see what he looked like.

Yesterday my fiancé was messing with my phone and he found the picture of our son wearing “girly” clothes and when I say he flipped out!!! It got so bad that I literally took my son and went to my moms house just so he could cool down because I didn’t want my son to hear us arguing. He kept saying that if our son turns up gay that it’s gonna be my fault (you’re born gay I’m pretty sure) and that every kid is curious about things that they shouldn’t mess with he ask if he was curious about touching a hot stove would I let him do that and I’m just wondering if it’s really that big of a deal? I personally don’t understand what the big issue he has with our son being gay is. He should want him to be happy and his sexuality shouldn’t determine how he looks at him as a person. I don’t think he really is gay he was just curious but if he was I would still love and support him. I’m so disgusted by my fiancé’s behavior right now I don’t even want to go home because I don’t want to start another argument and I know that I can’t talk to him about it because he will get mad and start yelling and I always break down when people yell at me and it makes me want to get away from that person so if I go back it will just start the whole thing over again... I don’t know what to do.