Don't automatically give your boyfriend the last piece of chocolate!
Some of the things that girls do that they think are loving things to do actually don't have that effect--as far as the guy is concerned. They're just taken for granted as being they way things should be.
The girl might think she's building up a two-way relationship. She thinks, 'If I'm loving then he'll be loving.'
The boy just thinks, 'It's natural that she'll do what I want to do--that's what women are for!'
And if they don't actually think those exact words, they act as though they do!
I have so many patients with marriages falling apart where the men will not re-examine these things. They just think that's how it should be.
Females need to be aware of this danger in a relationship, right from the start.
The earlier on a woman finds it out the better.
If you do come to a point of sacrificing or giving up then it's because you've chosen to do that. You both understand what is involved and what the cost is. It's not taken for granted that it should be like that.
If you've grown up with brothers who have been allowed to take, take, take then you have probably got used to it.
To change things you will need to assert yourself in little ways. Practise on your brothers, then try it on your boyfriend. If your boyfriend doesn't get the message then drop him.
Perhaps your parents are the models for this all-give-and-no-take relationship. If that is the case then look at some of your friends' parents. See how they operate. You might be able to learn from them.
In any case, talk about this with a friend who you think will understand what you're on about.
And if you can't do something about the family you live in now, make sure it doesn't happen in the family that you choose to live with when you're an adult.