What stuck out for me is when you mentioned how you can go along being fine for a while and then struggle with feeling depressed. Often this can take place if you are dealing with an individual that actually has you living around their cycles. This is often what can present when the other person is a binge alcoholic and never actually worked through their own issues but instead began to self medicate to avoid their own issues and insecurities. A typical red flag is what you described in how you struggle and then when you say something you end up with deflection of what you point out, then the partner makes it about YOUR faults and even accuses you of not being able to handle conflict or even being passive aggressive. Sometimes the so called "great guy" has a problem you are not seeing clearly and as I mentioned, it could be due to something like a drinking problem that you may not be seeing. A lot of people often miss that problem. That is what I experienced with my so called "great guy". Surprisingly, this happens a lot more than people realize so that is why I am asking you if there is some of that taking place in your relationship. It's often something that is overlooked.