Let me think here...
Self_Control I believe that you make some valid points most definatly. Women, at least most women's attraction, is somewhat turned off by a man's tears. But I don't believe that it kills it at all, but it certainly doesn't help.
But if you ever start to say that you have the ability to completly CONTROL your feelings and your emotions then you are living in a false reality. Just because you hold back your tears does not mean that you are controlling how you feel, but rather you are controling your reaction. Attraction is a feeling, and you know attraction is not a choice made by someone.....sadness, happiness, these are not choices either
We all, whether we believe it or not, will at some point lose control, because we are all human, I don't care how good you are with women, or how confident you are. The only way to not lose control of yourself due to your emotions is to release them. There are many ways to release these types of emotions, crying is the most common one. Now I don't recommend that you cry in front of a girl, women want a man who is sensitive but also who has a pretty good handle on controlling the effect emotional things have on them.
If you just feel the tears start to come...excuse yourself to somewhere private, or talk to a family member or a close friend or whatever. Once it is out, it will be out of you and it won't fester inside of you later.