Note that this is a broad and stereotyped answer.
As to any rule, there will be exceptions.
So why would men be less likely to fall in love with female magician ?
First, the time period : people did fell in love, but wedding were not often a matter of love, for neither spouses. At least not the first ones. At best, you hoped for mutual respect and put some efforts into getting your spouse to like you.
Second : Sorceress are being of power, they will attract alliance of power, not a peasant that barely have a hut to his name (if he has a name)... or will they (that's the whole question) ?
Third : If you are in position to propose to a sorceress and hope to be taken seriously, you have people to do your laundry and dishes and you can probably pay for magic healing if need be.
Fourth : Love is a fickle feeling, with much less social constraint than... formal social pairing. We have a lot of stories of impossible love, despite class, origin, condition, whatever.
So I'll alter a bit your question :
Why so very few proposition for someone who would bring so much into a family ?
To be a serious explanation of bachelorette-hood you will need to mix several of those.
1) A risk that no heir will be born.
A magician life is not a peaceful one. Accident happens, and even if you count on nannies, mothers must be alive and not too shaken on a regular basis to carry to term.
2) A risk that one's heir will not be his.
Even if the sorceress has a child, they are often sent away or just simply gone on their own errand. Marriage goal was alliance and posterity. Having a virgin wife was the only way to know one's child were one's child. So if one's wife is always away, wherever, with whoever, it's hard to be sure of her chastity.
3) Sorceress are high maintenance.
Their magic research might cost more than some kingdom can afford. Even of they can level a mountain, it's not something you often get paid for. A dress is a dress. But the heart of a dragon is slightly more complicated to obtain. And, even worse, some can't live without those things.
4) They tend to hog the power.
Yes your spouse will be able to dispatch a whole army of your enemies. But there is a high risk that at some point they will try to kill you or get you killed. Maybe it's pure paranoïa, maybe it's an educated guess as several of your neighbor have learned... or never get to learn, as things are.
5) They are volatile.
Of course, you don't sleep together most of the time at this social level. But sorceress are known to have... accidents. Where some people sneeze, Some sorceress change their spouse into frog (it might be reversible), or their house into balls of fire. Even if it's involuntary, it's a huge risk.
6) They live long life.
After the first three dead loving husband, after the first 12 dead children, Is it still worth it ? The sorceress themselves will spurn marriage as they know of the heartache they are.