Re: Is he Serious or just playing around?
Surprise…?
No it does not mean that you “should be taken for granted” but I don’t blame him for thinking it was an acceptable request from you. I think once you’re in a relationship with someone and comfortable with the other person…these things pop up (no pun intended :D)…but you definitely dont’ have to comply if you don’t feel comfortable.
I wouldn’t advise anything of that sort until you were married 
If, all other factors considered, he’s a decent guy…just talk to him about your boundaries and depending on how he acts afterwards, you should decide to dump him or not…