most people I knew needed 1 whole year to get over their first love, especially if it was that teens growing-up-with-your-lover type of love. The next one would take anything within 2 to 6 months, given that it was intimate and based on deep feelings. More important is the way they broke up with, if it ended with the buy being bored or fed up with his girl then it won't take him any time to move up to the next one, but if it was the girl who's been mean and playing around, or simply as if she cheated, replaced him with another, or got married, then it's the whole one year thing I talked about before or even worse, some guys can never get over the fact that they loved a girl and she stabbed them in the back.
If we're talking about a relationship based on lust and lacks friendship from the start, then it's usually not dramatic at all for a guy to get another in no time, let's say that's the 2 months relationships type... another thing I have noticed, the time it takes us guys to deal with breakups is similar regardless of our personalities, but the way we deal with it is different, some might just want to sleep, some want to keep crying like babies and be alone, some want to cry in front of others, some start looking fast, others would just keep it inside and wish she'd come back to them, some would just want to be single and drop thoughts on their part. But in the end, the thoughts of the girl being with another guy is what hurts during a break up the most, jealousy feelings and such.