In retrospect I think my comment sounds like I’m just excusing being sort of crappy if you’re humble about it.
I wish I’d included the sentiment that we’re all trying the best we can — because being a good partner should be the goal for any relationship.

Even though I’m currently only with my wife, I’m right there with you. I don’t want to add anyone to the mix unless their addition is very carefully considered.
I speak better in metaphor sometimes: It’s kind of like physics, almost. Imagine that we’re touching everyone in our life. If we allow someone to connect to us, they are going to impart their own momentum and direction. That is going to ripple through every connection we have, even if we aren’t able to measure or observe it. So we better make sure they don’t hit us so hard that pieces break apart or get damaged in the process.