This may sound very stupid. My boyfriend fingered me twice the day after my period ended last month. I never gave him a hand-job and he says no pre-cum ever came out of his penis when he got an erection. He washed his hands thoroughly before I came to his house and he took a shower. The last time he ejaculated was 24 hours ago when he masturbated in his bed. The first time he fingered me was about an hour after I arrived at his house (mostly just heavy petting, no penetration). The second time was about 2 hours after the first time. He went to the bathroom and washed his hands before this. This time he stuck his finger in about 2 inches for a few seconds. He also ate me out for a few seconds. I got what seemed to be my normal period except for the fact that breasts hurt for 2 weeks beforehand instead of the usual 1 week and my period was about a day short. My breasts stopped hurting once my period started.
Could I have become pregnant from any dry sperm that was left on his bed sheets from him masturbating the night before?

That's not a stupid question at all. If it's something that concerns you, then it's a worthwhile issue to research.

Sperm are not really meant to be dried and reconstituted; they're not really like sea monkeys. Sperm won't survive more than about 20 minutes in an inhospitable environment (like toilet seats, hands, sheets, the wall, or whatever). They can survive for much longer (days, in fact) in a hospitable environment, like the female reproductive track. So as long as there was no fresh, wet ejaculate on anything, there's no chance there were any viable sperm present. Also, the likelihood of transferring ejaculate from one surface to another and causing a pregnancy is pretty darn low. Again, sperm are pretty delicate in most environments. So unless you sat with your bare genitals directly in a pool of very fresh ejaculate or had manual sex when your partner's hand was dripping with fresh ejaculate (or pre-ejaculate)...you've got nothing to worry about. Further, as long as you've had a period since then that's basically normal for you (give or take a bit), which it sounds like you have, then you have nothing to worry about. It's not possible to have a full period and maintain a pregnancy.

It was a good step having your partner wash his hands before having manual sex. From your description, there was no pregnancy risk there period, but by washing his hands you significantly decreased your risk of picking up some kind of infection. Hands can be pretty dirty, even if they don't look that way, so washing is always a good idea. You can further decrease concerns by using precautions like condoms, gloves, lube, and dental dams for any type of sex that you're having. By taking all the necessary steps to protect yourself, you can decrease your STI and pregnancy risks AND your worries. It's really easy to use protection like condoms and gloves and is well worth the weight that it takes off your mind. Also, if you are having these types of concerns and you and your partner can't settle on precautions that you are comfortable with, then that's a good sign that it's time to postpone any sexual activities until you are comfortable. Sex (of any sort) is a totally optional activity...and it's just not worth it to have that level of anxiety about something that you can stop engaging in until you are ready.

(As a final note, it would be pretty unusual if your partner had an erection for any length of time and really had no pre-ejaculate ("pre-cum") whatsoever. Men don't really even feel pre-ejaculate when it's happening. That is just a part of the process of sexual arousal for men and it plays an important part in the reproductive process. So I'd be really surprised if your partner actually had none. It's more likely that he simply did not notice it happening. You just want to be aware that it's probably not exactly true if your partner says there was no pre-ejaculate and if you have contact with pre-ejaculate, you may have pregnancy and STI risks.)

You may want to check out the following articles:

• What's the Risk? Easy Pregnancy Risk Assessment
• STI Risk Assessment: The Cliff's Notes
• Safe, Sound & Sexy: A Safer Sex How-To
• Where DID I Come From? A Refresher Course in Human Reproduction
• Margaret Sanger's Disneyland: Choosing Contraceptives
• Condom Basics: A User's Manual