I've turned down more than I'm proud to admit too...
When you're in a target rich environment, it's fine. I used to work at a bookstore and it was so weird for me when I first found women regularly hitting on me. I got a bit of attention at uni, but mostly kept to my small group of friends. Meeting new women every day does something that just makes you super-attractive or something, I don't know. Now that I work in an office and see the same people every day, I regret all my missed opportunities...
But as you say
"I'm pregnant, now you have to take care of me the rest of your life".
I am not interested in this, or STDs, or any of the long term problems that come with sleeping around too much.
And I still get girls who I know (former work colleagues, friends of friends, etc.) who occasionally "throw out some bait" then I bite, and then they pull away. I'm like, if you're not interested and are just looking for attention, F off. If you are interested, I don't play games. That simple.
I've probably also lost a lot through my "no bs/mind games" attitude.