Please Help Don't Know What To Do

Hi I am 27 now and at the start of the year I remember thinking I would never find a man who loved me that I love back I had never had that before and that is all I ever wanted. So many men have hurt me, used me and abused me in the past and I have been left heartbroken so many times I never even had a real boyfriend before I used to take a lot of drugs in the past for years since I was 15 you name it I used it my main problems were speed and weed but the last 3 years I helped myself to stop taking drugs and I was really happy being drug free the main reason I wanted to stop taking drugs is I was worried I would die I never really cared if I lived or died before until I got my dog and I stopped weed because it would make me angry paranoid wreck who was too scared to even go out sometimes anyway about 5 months ago I met my new boyfriend and fell in love he is the first man I've ever fell in love with that loves me back and he treats me so well we are together everyday the only problem is he smokes weed everyday from the minute he wakes up he has a spliff and most weekends he will take a bit of coke or ecstasy he can function like that though and not get addicted or let it effect him really he has his own successful business own home and he goes to work every day with me drugs really do effect me they make me moody and emotional and a wreak and I can't just do a little bit either since I met him I have been smoking weed every day again as well and taking coke or ecstasy or both most weekends and I feel really bad I don't want to take drugs anymore I am scared of the serious health risks and they just don't make me a very good person I have been really moody with my boyfriend lately I keep saying to myself I will just let him take his drugs and say no but I am just too weak I keep taking them with him I really don't want too how can I be stronger and just say no when he is using? I really don't want this relationship to end but I don't know what to do I have spoken to him about it and he has no intentions of giving up drugs he doesn't think it is a problem which it isn't for him in some respects but I still worry about his health especially as he is older than me
basically I need help and advice of how I can give up all drugs starting from Monday again and still be with my boyfriend and see still see him every day even when he is smoking weed every day and taking coke and ecstasy most weekends and be able to be around him and not take any drugs at all and be able to say no I've never been able to say no even though I really don't want to be taking drugs before when I stopped taking drugs I cut out all the drug users out of my life but I don't want to cut my boyfriend out life wouldn't be worth living without him