Either way, it is only your choices to be ethical and responsible or not, which will differentiate your actions between cheating and polyamory.
Most likely he is already worrying that you will break apart. You are who you are and you have made the choices you have made. If you do not tell him, if you act as if it is something to be ashamed of then it is more likely he will think it is shameful.
Sex itself is not a need. That doesn’t mean that it isn’t important, just that we can choose to define it differently and this may be more helpful in figuring out what to do. It’s important that you reconsider your perception of sex as a need, because–in a hopefully hypothetical and extreme case–if you consider it a need you will have to add more and more people to your relationship if they stop having sex with you (for whatever reason!) and you risk treating them as objects to fulfil this ‘need’. Such a paradigm is unsustainable.
The only way for him and his self esteem to improve is for him to take responsibility for his actions and emotions. But that must be his choice. Can you reach him?
Only by continuing to assume your own agency and by taking responsibility for your agency–and only yours.
If he cannot get what he wants from you, if he cannot force you take responsibility for his actions and/or emotions, he has very few options available to him.
If we consider our actions and abilities as a function of an inevitable pre-programmed script, then we cannot manage them, or change them. This is why you feel lost and out of control. But you have chosen this narrative (it is the easiest script for you–ask yourself why it is that you choose a state of ‘no agency’ in your relationships).
To boil it down to basics, right now there’s two sides of the story. What you can do to influence others’ opinion of your relationships, and what you can do for your son, so that he can still feel good about himself when faced with (the perhaps inevitable) society backlash.
She’s 27 years old, it’s time to let go. If she does have mental health issues as many might over the course of a lifetime, you are only stigmatizing her by under-estimating her capabilities and agency to sort it out herself. And if she does face challenges she doesn’t need you to sort it out, she needs a therapist (and that should be her decision). Be her support, but support her in being an adult.
Why should you consider not being romantic with your boyfriend in front of your child?
Romantic behaviour infers intimacy. For me, it’s not about whether intimacy is a harmful thing (or a ‘bad’ example – we’re not talking sexual behaviour, just ‘closeness’). It’s about the signals that you send your child regarding your new partner. Your intimacy with them is a demonstration of trust. Your child is attached to you, and implicitly trusts your judgement.
I want to be absolutely clear, that even though you are in a power exchange relationship, this does not mean you have to give up control of your life all the time. In a healthy D/s dynamic, you have the option of stopping the play at any given moment.
And it sounds like his involvement with this woman makes you feel unsafe.
Where does your own responsibility lie? Well, because women are used to emotional labour and programmed by society to run the ‘carer/nurturer’ script, it is perhaps also the case that you took on this work – in all likelihood without asking for help, without communicating your wants, needs and expectations – and are now left feeling resentful.
I don’t see that you are using people for sex (even if this is absolutely acceptable if you both consent). You are looking for connected sex which occurs within the context of a loving relationship. You want both. And to me, that sounds just fine.
Even so, sometimes when people love us, the compassion they feel for our ‘sorry’ state, prompts them to take actions to care for us which might not be the best way forward for either of you because eventually one or both of you will start to resent the perceived ‘control’ that binds the two of you.
You – no one else – is choosing to justify a self-imposed veto on your potential polyamorous experiences because of her experience of her emotions. It sounds like you are acting as her rescuer–by abstaining and enabling–in the drama triangle (ah that pesky drama triangle pops up in so many of my answers).
It won’t end well for either of you…
Generally, by the time you are Real, most of your hair has been loved off, and your eyes drop out and you get loose in the joints and very shabby. But these things don’t matter at all, because once you are Real you can’t be ugly, except to people who don’t understand.”
― Margery Williams, The Velveteen Rabbit
This is not an excuse to act without sensitivity, but there are limits to how many eggshells you can tread on, without eventually resenting her for your choice to do so. Because make no mistake, even if it is your choice to walk on the eggshells, you are bound sooner or later to cross your own boundaries if you’re bending over backwards to accommodate someone else.
Second guessing someone else’s reactions is therefore unlikely to be productive.