Love can be quite paradoxical at times. A guy will say that he totally loves a girl, yet she does not feel the same way about him at all. And he will say that he will do anything for this woman, yet she wouldn't be bothered to do much of anything for him. What's the point of falling in love with a woman if you cannot get the girl in the end? I say that because to be honest, I have dealt with trying to help so many guys who are stuck on a woman who does not reciprocate their feelings and no matter what you might try and tell them, they are fixated on the fact that she has to be the one.
It does not and really should not be that way. It should be a lot closer to 50/50 than you giving her your all and her giving you not a single thing. So, why do guys end up in that weird dynamic where they are willing to do just about anything for a woman when they know that she will not do the same thing for them?
I think it comes down to these 3 things most of the time:
1) They have equated physical attraction with love.
This comes mostly with inexperience, though it really can happen to anyone. Guy sees a girl who for some reason, looks exactly the way that they want their girlfriend to look like. So, right away, in just a matter of mere moments, they are already in love with her. She does not have to even look their way and they already know what they feel. This is really just massive physical attraction getting confused with the emotion of love. The reality is... he loves to look at her more than anything else.
2) They are so lonely on the inside that they need to fall for someone.
This is also very common. Lonely guys fall for a woman pretty hard and pretty fast. And lonely guys quite often will deny that they are lonely, but everyone else around them knows it. When you are feeling really lonely, then there is usually a part of you that is just dying to meet someone, anyone to take that feeling away. When you do meet someone, even if there is not really a strong connection, then you take things to that next level very fast. It's like the woman becomes the lonely guy's salvation and that's something that will definitely make someone feel like it must be love, when all it really means is that they are lonely.
3) They've met a woman who knows how to play a guy and they don't want to admit it.
Pretty frequently, I will talk to a guy about his problems with a woman whom he is in love with and he's talking about how she does not feel the same way and something becomes pretty clear. He's willing to do a lot of favors for that woman and so, she gives him a little flirtation here and there so that he keeps coming back to do things for her. While he is falling head over heels, she just sees him as her errand boy.