Hey there- I'm a bit late to comment, sorry, but thought I'd add my bit in as a fellow female on here I think ultimately, it sounds (from what you're writing) that in this time apart perhaps you need to think about yourself as a person as well as a person in a relationship- if that makes sense? it reads a bit as if you're expecting your happiness to come from the way that he treats you/ reacts to you, which is definitely a recipe to be unhappy. I'm really sorry if that sounds harsh, I'm just trying to say (on half a cup of coffee, so I'm struggling here!), that perhaps you're placing too much emphasis on him in terms of what is going to make you happy- perhaps if you think about what you really want, how you see your life, what you need from a partner (rather than focusing on what is lacking), then you might be in a better position to sit down with him and articulate that, and see what his response is?
In my experience, doubts always creep in from time to time, I think that's just human nature, the challenge is for you (and only you can do this) to work out if it's because you genuinely do need/ want more, or because you as a couple are not communicating what you want/ need/ expect clearly, or that you are unhappy/ unsure for other reasons and are placing that on your partner.
I really hope you are able to figure out the right solution for yourself- after all, we're all seeking happiness
If I can offer my humble opinion after such a thoughtful post. The seeking of happiness has to be approached with an acceptance of it being a temporary nature when "found". It is the same as sadness being a temporary state only, both will occur for periods of your life and more so for some people of a certain personality or to be precise: chemical set up in their brains. Which is fine, its what you are and you are more likely to be compassionate to others and sensitive to other's feelings based on the depth of emotions you have experienced to contrast on both sides.
Why am I saying this? Because both states of happiness and sadness are opposites on both sides and therefore impossible to attain permanently, even though we naturally aspire to only one of them two states.
An achievable median therefore is better to seek, and that is contentment. Contentment is achievable for long periods and although there will be natural flux with periods leaning towards happiness or sadness, you can achieve contentment for long periods of your life.
An important facet of contentment is acceptance of it being a target and that things won't be perfect. A good tool for facilitating and training your brain into contentment ca be mindfulness. Either an app, a CD, a book or just a moment to do some breathing exercises. It begins acceptance for many which slows the brain down and can instigate the right environment for contentment to begin.
Don't chase happiness, chase contentment. Happiness will occur often during contentment.
A bit deep so soz, I'll go back to calling people scruffs now.