A Capricorn/Aquarius relationship isn’t ideal, but it can work with much effort. If you have made it work for three years, there is something there. Aquarius and Capricorn have completely different approaches on life. Try looking at things from his perspective. Ask him to disclose his thoughts with you, and let him do so honestly and freely. Aquarius is never self-sacrificing, but they are always humanitarian, or at least progressive. Capricorn is very self-sacrificing, and is a philanthropist, most likely a conservative one. Capricorn has a very sharp tongue, and knows how to use it. If he wages an attack on Capricorn’s ego, he will be shut out and shut down.
If he starts nitpicking at your character regarding something completely unrelated, leave.
Aquarius and Capricorn make a wonderful one-stand. They can be really good friends, too, if they have other influences in their charts that indicate that. Normally, when they date, it is short lived and infuriating for both parties.