Try swimming. I love it and it takes away stress for me. It takes a few months to learn how to swim properly but it's worth it.
I think that it's pretty much the most stress-free sport aside from golf :P and tennis/badminton.
You could actually try badminton or tennis, but they might be just...
No, you have the right to deny him sex. If he does anything, you'll know he's in the relationship for sex.
You have the right to say no. Remember that, and don't listen to anybody, especially guys, who say it is wrong.