Hi.
Good questions. Let's examine each issue separately:
1. Your boyfriend wants sex nightly. It seems to me that by telling you he wants you to be the aggressor, he may be expressing that he wants YOU to be the one who expresses desire for sex. Perhaps this turns him on. Many couples discover that they have disparate desires. In order to understand this and work out something mutually beneficial, you need to communicate about this. Sit down and discuss what you each want, without blaming or getting angry.
2) If your boyfriend finds his erection coming and going, this doesn't necessary indicate a problem. However, if he's finding his desire fluctuating, this may also be due to something that the two of you need to discuss. Please understand that Viagra doesn't affect desire. It's solely for physiological conditions which prevent blood flow to the penis. If your boyfriend isn't having erections upon awakening, that's a dead giveaway that he has such a condition and should see a urologist to determine what's going on. If he DOES have erections at times other than when he's being sexual with you--well, you get the idea.
3) I do think the evidence shows that his desire is being affected by something going on with him emotionally or in your relationship. He's looking for excuses, such as not wanting you to get pregnant. You say he has a hard time relaxing and focusing on what is going on. This can definitely interfere with sexual arousal.
In short, your boyfriend is an unknown quantity, since he's not writing to me, and I don't know what his issues are. Enough guessing. You know what I'm going to say: you have to talk. And now.
If you don't feel you two have the skills for this, seek out a counselor who is trained to help people talk to each other about their sexual concerns. Best of luck to you. Dr J
bust out a strap on, he'll never ask you to be the aggressor ever again.