Bad kitty

Ok so i have a 3 year old Maggie. I have had her whole life. She has been through a lot. 3 bf's, 4 moves, and her adopted kitty mommy's death (Tigger passed of cancer last summer)
She has always had behavior problems. When she was a baby my ex was home with her all the time and played with her roughly.
She plays by scratching and biting. She hates being petted anywhere but the head. I tried saying NO firmly and then getting up and ignoring her when she bites and scratches me. She hisses at my current bf sometimes.
She refuses Strangers and as gone as far to attack my sister and brother-in-law.
She is affectionate in her own way. She weaves in and out of my legs and sits on me when i sleep (not when i am awake though).
I have bought her toys. She has tons of them and i give her play time in the morning before i leave for work and when i get home from work.
She still bites and scratches. How can i get her to stop.

She has been through a lot

A lot of cats don't like being petted. My Rosie will only be petted for so long when she'll go to give a quick bite, but i just stop because thats her way of telling me she's had enough.

Even strangers she'll run away from until she gets to know them.

Try getting your bf and friends to give her treats to win her round, but the thing with cats is, you can't make them come to you, they do it on their terms.

My Emma will beg to be petted, but if you try to pet her when she's not asking you to do it, chances are she's going to be cranky with you. Your kitty may never be a lap cat, but if you give her lots of treats, are gentle with her, and let her approach you on her own terms, you may find she comes around rather quickly. Give it time and patience, and realize that even if she is never a cuddlebug, she's still a great cat who loves you in her own special way.

My feral girl is a lovebug, but only when she approaches us first.
My 11 year old that I've had since she was 3-4 weeks old is a cuddle ****, be even she has her limits as to how much petting, where and when she'll put up with.
Our oldest male after three years only just tolerates me, though he is, on occasion, cuddly, but he will flat out bite you when he has a mind to.
Neither of our 1 year old boys seeks attention much, but when they do, it is lavished upon them.

And sometimes, a lot of changes throughout a cat's life sets them off balance.
Sounds almost to me as if your kitty is afraid to become close to your boyfriend, because she's lost the other humans (ex-boyfriends) you had in your life, and she doesn't understand why.

Don't expect anything of her. Ignore her except to give her food and water and scoop her litter pan and see to her health needs. Some cats just don't want what we want them to want. Of all my cats, only a few of them will allow me the privilege of treating them like a pampered pet, and well, my arms at times makes people ask me if I suffer from domestic abuse! LOL

Lower your expectations and take the pressure off this kitty. As Susan said so wonderfully- you can't make a cat do anything except on their terms.