"My partner always wants to push the sexual boundaries."
My partner always wants to try new things when it comes to sex. Sometimes I'm as eager as he is. But other times I don't want to do what he suggests and he hassles me until I eventually give in.
The thing is, the minute we've tried something, he goes off the idea and wants something new. I don't know if I disappoint him or if he is just always looking to push boundaries, but I am worried that one day he will go too far and I won't be able to give him what he wants.
Your boyfriend has a thrill-seeking libido: he needs new stimulation, constantly, to satisfy his sexual hunger and curiosity. There's nothing essentially wrong with this, but it does require a lot of effort to keep thrill-seekers satisfied.
And you're right - some need increasingly 'out there' acts to keep getting the kick. Things like erotic asphixiation - robbing the brain of oxygen to intensify the feeling of orgasm though self strangulation - are tried in extreme cases.
So your boyfriend might well suggest something you're not prepared to do - and you're quite right to say no to him when that happens. You're also right to say no to doing things you simply don't fancy. What's not right is him hassling you until you say yes. That's sexual blackmail.
You need to sit down with your boyfriend and tell him you understand he likes to push the boundaries and you're open to exploring some new things. But you won't be forced into trying things that don't appeal just to satisfy him and you're concerned what he will do if you don't agree.
Can he get the thrill without the consequences by satisfying his urges through watching porn? If he can't and insinuates in any way that he'll be unfaithful or leave you if you don't comply, you leave him before he gets the chance to do either. Never, ever kid yourself someone loves you under these circumstances.