Boyfriend probs :P

So I've been deeply considering buying a dildo because my boyfriend's sex drive isn't as high as mine and when he wants to and we do I'm never satisfied. What are some good brands or is there any advise you lovely people have for me? The catch to this (or main reason I haven't purchased one yet) is my boyfriend is super against it because he thinks if I have one he won't fit anymore and he gets angry whenever we talk about it. I've tried to tell him it won't and even if it does it won't do it enough to notice. I'm not sure what to do help!?