There's a lot going on in this statement. What comes up for me is:
2) Self-love / External vs Internal validation
3) Attachment anxiety / types
5) Cause & Effect
Ultimately you're never going to know what is going on in someone else's head and to be honest it's their behaviour that you experience so you might benefit from not looking beyond that.
Expectation - the issue with this is that it's based around judgement - what someone 'should' do... unless it's something that you've agreed to in your relationship dynamic then all you're doing is setting them up to fail and yourself to feel disappointed. Lowering or removing your expectations can really help and it means you're not focusing your energy on whether or not your partner does or doesn't do something, more appreciating what you do together.
Self love / External vs external validation - once we're born we're permanently detached from the original source of our life. Seeking to find love and life and the answers in another person removes a lot of the control and power you have in your self and your own awareness and decision making. If you can, next time you think about doing something caring for your partner, why not do it for yourself instead. Often self-love benefits both partners as it puts you in a better, happier place.
Attachment anxiety / types - it sounds like you might have an anxious attachment type and they might be avoidant. It's worth reading up on attachment types and once you've understood it and identified what parts of your behaviour may be reflecting your 'type' it may well be worth discussing this with your partner and coming to some agreement as to what might work better for both of you. Again keep you expectations low and if you are anxious be conscious that you're probably going to over think and over act so take your time and think twice before you act. Observe first and then when you've given yourself a few days to think about it... then discuss. If your partner is avoidant then you may need to be gentle about how you introduce the new information and give them time to digest.
Reciprocity - is super-important in any relationship. The concept of unconditional love is great though in reality it's not easy, particularly if you're a giver and they're more of a taker. Even this can be a misconception in that you may be giving a lot of what they don't want but if you place a high value on it then it's going to feel imbalanced. Similarly, they may already be putting in a lot of effort already, even if you think they're not so be careful. A lot of this comes down to communication and setting agreements about what you would like (not need) and what your partner is prepared to do... voluntarily. Forcing things in a relationship leads to resentment so don't do it. Ask them how they would like it to be or work and tell them what you would like and give yourselves some time to think about it before you pressure a decision. Even when you've made a decision don't be too strict. Having said that it's important to have boundaries and rules that you agree with each other - rules are unique to humans and they are there for a reason.
Cause & Effect - Try not to mind read your partner. Let them tell you what's going on and learn to accept their response. Challenge yourself on whether you really need more than they are giving. Why can't they give you what you want? Are you asking too much? Is it reasonable? If what you're asking for is reasonable and your partner isn't prepared to give it then that's a clear indication that something isn't right. You then have to place this in the wider context of what is right and wrong in your relationship and decide whether you can truly accept this person being that way.
We're all different people. If you aren't happy with your partner and they way they love you, it's either because you're not right for them, they're not right for you or you're not right for each other. Yes it's good to adapt to another person, but too much adaptation is very hard to maintain without causing damage in the long-term.
Give yourself some space, spend more time doing the things that make you feel good about yourself and keep heading in that direction until the balance feels better.