How can I have more pleasurable sex when my partner's penis is too large?

I have encountered a problem I never expected; my boyfriend is quite simply very large. I am unable to perform oral sex except for the first couple of inches due to the girth, and vaginal sex is not totally satisfying for him because he is too long and cannot fully penetrate without causing me significant pain. I've seen my doctor, and am reassured that there is physically nothing wrong with me — no infections or scarring, but am finding it difficult to come up with a solution. Any suggestions?


Do I need to use condoms if my boyfriend might have an STI and not know it?

If my partner and I have been monogamous for three years (and I was a virgin before we met) and my partner tested negative for the HIV virus (twice, about two years ago, with a six-month gap between the tests) is it safe for us to use a birth control method other than a condom? That is, are there still any STDs that my partner might have without knowing it, that we should be worried about, even though nothing whatsoever has seemed wrong with either of us for three years and my partner has had several regular annual physicals in that time?