A WE problem or a ME problem?

As an anxiously attached person, I struggle to sort out how much of what feels "missing" in a relationship is actually about the relationship, vs. what can/needs to be fixed inside ME.

My boyfriend of almost a year and I have noted that I experience a great deal of relationship dissatisfaction around my period. Like clockwork, I break down every 25 days.

Relationship anxiety that I can often work through on my own becomes unmanageable in the hormone whirlpool and I force bf into long, searing talks attempting to get what I need. We never fight, no one raises voices, walks out or says cruel things. But we do seem to have the same conversation on a loop without resolution.

Basically, we’re both pushing at the edges of our disparate comfort levels for TOGETHERNESS VS. AUTONOMY.

Right now, we’re spending a little more time together than his ideal, a little less than mine. Plus, he sometimes makes decisions unilaterally that I feel we should make together. 

The time we do spend together is quality time, even if we're not doing anything special. He's consistent with me, there's no intermittent reinforcement. When he's with me, he's 100% focused on me. We solve *most* problems very well through communication and compromise.

However, at this time, MORE of his energy flowing towards our relationship is just not on the table. He’s just not interested in spending more than 3 or 4 evenings a week and occasional days together. I agree it's too soon to move in, but I still find myself resentful when I spend nights alone, and as usual for me in a relationship, wanting more than the other person is willing or able to give.

In the interest of his personal growth (he's not long out of a long term monogamous relationship) and my ever-shifting sexuality, we're also practicing ethical nonmonogamy, but that's a whole other thread: Polyamory for the Anxiously Attached . Intellectually and philosophically, I'm ok with that, except that his secondary relationship take away some of his energy flow from me (he sees her once a twice a month.) Though I'm talking to a couple of promising people, I don't yet have a connection like that of my own.         

I can see the work I need to do on my end, namely fill my life with more social and creative stuff, more travel, build up my life so I don’t feel his absence so keenly. Of course all that is easier said than done, especially during a pandemic. 

I’m a little lost on how to know how much of what’s missing in my life is between US, how much can be fixed inside ME. Common wisdom says trust your feelings, but what if your feelings are affected by old wounds and a general pessimism about relationships? It's hardly his fault that I put too much focus on him, then get discouraged and withdraw or protest until he's in tears knowing I'm about to leave him. He reassures me constantly he loves me, doesn't want to break up, like ever, and isn't trying to replace me with another woman.

He's more securely attached. He is able to put down the relationship and go do other things and assumes when he returns I'll be emotionally the same spot he left me in. He is less jealous and possessive, more supportive of me finding other partners.  

Sadly, while he's off living his best life, even if he's just out with his guy friends, I'm often feeling wronged and breaking up with him in my head. My eggs are so scrambled I struggle to recognize if someone is treating me well or not. 

I don't want to do something I'll regret, dump him because I'm insecure and impatient. We genuinely enjoy each other, are amazingly sexually compatible (I admit this is very important to me) and we're open books with each other and complement each other well in many ways. 

I think what I'm asking is this: How does someone with scrambled eggs like mine sort out the boundaries between relationship issues and attachment issues?