My fiance says I am a buzzkill for not want to have sex?

I'm just not in the mood to have sex. Ever since I have gotten home from work he has been pestering me to do it. Pulling my pants down, kissing me etc. I have told him no multiple times and he'll ask why now? He told me I was a buzzkill and walked out of the room shutting the bedroom and his office door (he was playing video games) Saying he will just masturbate again. He'll just straight up ask if I want to do it. Example: Wanna have sex? That doesn't put me in a mood maybe for other but not for me ( I have told him that before) I know I am not a buzzkill for not wanting to do it but he makes me feel guilty...I thinking I am just venting but honestly don't know how to deal with this. It isn't the first time he has told me it.... It's like he thinks he is entitled to

M28

F24