Sarah asks: "I have been dating a great guy for a little over 5 months. We are both in our 20's. He has a very demanding job and is extremely busy, while I am a college student with a much more flexible schedule. Our sex life has always been great - we have awesome bedroom chemistry, and it has always been an enjoyable, zesty enterprise for us both. However, he decided to stop drinking for a month - he felt like he was doing it too much. He has lost all interest in sex - we haven't done it in about a month. He says it is because his emotions and thoughts are all changing and becoming clearer because he has stopped drinking. Also, he is on antidepressants, and I have read that they can decrease libido. He is still very affectionate - we cuddle every night we are together, hold hands and kiss. I asked him if I had put on weight or anything since we started dating, and he insists that I have nothing to do with his lack of libido. Does this seem plausible? If this is a temporary thing, it is definitely worth it for me to wait it out and be patient and give him time, because he is a great person. I just want to know if the reasons he gave me for this seem legitimate. How long is too long without sex, especially in a new-ish relationship between young people?"
First off, kudos to your boyfriend for realizing he had a problem and doing something about it. It couldn't have been easy asking for help, and I applaud his willingness to seek treatment. As I've gotten older I've realized that a partner who can admit when they've got a serious problem and do something about it is a rare gem indeed. Sure, he's in the early stages of the process, but it's a good start.
As for the questions about your sexual frequency, many anti-depressants decrease a person's libido (see: The Sexual Side Effects of Antidepressants or this poll, in which 88% of readers say yes they experienced sexual side effects). There are ways to mitigate this issue; your boyfriend needs to speak with his doctor about his options.
In the meantime, I highly recommend reading When Someone You Love Is Depressed by Drs. Lauren Rosen and Xavier Amador (Buy Direct) or About.com's Guide to Depression, who has written about the topic extensively (10 Tips for Coping With Depression in a Relationship, What To Do When Someone You Love Is Depressed). Its a difficult thing to date someone who is depressed, so you'll need as much support as you can get (as will he!) during this difficult time. I also recommend, if you can, to talk to a mental health professional yourself about how you're feeling.
Don't forget however that sexual frequency decreases in most relationships when the initial honeymoon phase wears off - usually somewhere around three months to two years. This is normal and to be expected. No one could continue the initial rush of sexual frenzy or excitement of getting to know someone new forever; some studies are even likening falling in love to certain forms of Obsessive Compulsive Disorder - see Daniel Amen's The Brain In Love (Buy Direct) for more on this topic. It's a heady thing being in someone's company constantly, having lots of great sex, and connecting deeply with your partner - but after a while, the body can start to fight back and say, "Okay, back to work! Let's find a more healthy balance." From that little you've shared, it sounds like your boyfriend is trying to do exactly that. Is it temporary? There's no way to tell really, but I'll hazard this is just one step along a long evolutionary path, with its length determined by the longevity of your relationship.
So what can you do? I suggest you stop asking him if you've gained weight and/or if you are attractive to him anymore. By asking you are both reminding him that he's not satisfying you and thus not making you happy, as well as using negative self-talk to put yourself down. Of *course* you're still attractive and desirable! That hasn't changed in the five months you've been dating. The issue here is something much greater than you, and can't be taken personally. Can you start looking at your sex life as something that will constantly evolve and yet still be completely normal? Can you learn more about depression and how it affects your partner? Do you want to continue dating a man that is going through a major upheaval in his life, and support him through the unpredictable process? Those are your questions to answer, and no one but you can decide what's best for you.