When I was considering parenting alone, I knew I could only pull it off with significant outside support. I went to all three of my parents (mother, father, stepmother) and asked if they were willing and prepared to raise a child with me. When I got a trio of enthusiastic yeses, I returned to my hometown and began the babydance.
Bug is now a toddler, and my parents are deeply involved in her day-to-day care. Each of them has her for a full day a week while I work, and sometimes watch her at night when I socialize. She is a healthy, happy little kid in no small part thanks to their nurturing.
Recently, I made a somewhat-last-minute request that Mom babysit on a Saturday night. She was openly torn: she's been tired and stressed by her job and by a dear friend's illness, but hates saying no to something she is technically, scheduling-wise, skill-wise able to do. I heard the conflict in her voice and told her, "Please say no. Then when you tell me yes, I will trust it."
Understand that I am NOT good at accepting help. I'm proud and stubborn and I hatehatehate putting people out. If I think someone is overextended by helping me, the help does more damage than good. I feel guilty, anxious, and if I'm out doing something intended to be fun, I have a lousy time. But I've [mostly] gotten past my discomfort by the liberal application of this mantra:
trust people to say no
As I've harped before, unless you replenish yourself, you'll be useless to those you care about. The inverse of this is trusting those around you to set their own boundaries. You're never going to be a mind reader, so you have to take what people say at face value. Believe that loved ones will only offer what is free and safe to give.
This philosophy is doubly applicable in nonmonogamy.
If you choose to have multiple partners, you will be all-but-literally juggling people. In your attempts to be supportive, attentive, loving, GGG, etcetc, you're going to fuck up. A lot. Recurrently. A whole bunch. Often. Sometimes, you won't even know that you've fucked up, your head is so far up your many-partnered ass. So you need to cultivate connections where it's safe to say and hear no
When you enter a new pairing, or when you're doing maintenance on an existing one, tell your partner explicitly: 'if I ask for something that you can't afford to give, I need you to say no. That way, when you say yes, I know that you are doing so willingly and without causing damage to yourself.'
The longer I play this game, the more parallels I find between dating and parenting. Can't decide if that's amazing or gross. *sigh*