I think it depends on where you on in the spectrum of sexuality. Your own moral upbringing. How you were raised and what kind of relationships you've been in.
For me, I don't mind an open relationship. But I'm asexual, so I wouldn't participate in anything outside of the relationship I have with said person. People are all differently made, differently wired, their brain's connect in different ways to different circumstances. I'm weird in that I find sexual attraction outside of myself. I dissociate myself from any kind of sexual activity, so I find my pleasure in myself primarily, in finding something on the internet or a nice erotic novel or simply my imagination. Outside of that zone, I'm fairly uncomfortable with physical intimacy. I'm fairly repulsed by the actual practice of sex itself.
I also romanticize everything, so I'm more prone to being shocked when presented with the actual thing.
Anyway, your relationship with your boyfriend is perfectly normal. And it's perfectly normal to think that what you're doing is strengthening your bond. Because it most likely is. You can devote yourself to one person while having sex with someone else. Of course, consent is definitely a requirement for anything that you do. Consent goes a long way and that's where trust truly lies: in telling someone you love that you aren't okay with something and trusting them to adhere to that.
I mean, I'm fairly sure that it's all about yourself personally. It has nothing to do with morality aside from the consent you and your partner give each other (and consent they give and get from other people, obviously). It's not morally wrong to want or to have an open relationship. I think a lot of people make sex to be this big thing, something that carries emotional weight and that should carry that weight. That it should be the climax (pardon my pun) of a relationship. I mean, that's your prerogative, definitely, but to expect someone to feel the same as you seems ignorant? But, me personally, I find romance in the smaller things, rather than the act of coitus itself. To me, sex is just an optional physical act of pleasuring yourself and your partner. Neither selfish or selfless. You care for another as you care for yourself. It's kind of hard to explain. I'll just leave it at: I don't think sex is a big deal.
To be in a relationship with someone who's aromantic and not want to understand where they're coming from, though, how they feel, and instead judging them and telling them that their lack of monogamy is repulsive? That's a great way of telling someone that they aren't normal and that they should, in fact, feel repulsed with themselves.
Regardless, polyamory, being aromantic, and all across that spectrum. Just wanting to spice up your sex life? Those should never be considered negatives. Just because you're having sex with multiple other people doesn't mean you can't be madly in love with one person, dedicate your entire self to them. But maybe that's because I don't see sex as anything other than an act of carnality. Sex with a random stranger can be and mean something entirely different to sex with someone you've dedicated your life to, you know what I mean?
As an example, I can be in a relationship with someone who's aromantic. I cannot satisfy them sexually, but they can find people who can. However, even if I do give that person sex, they have given me, have offered me, have let me have something that none of those other individuals will ever have. I have his love. I have his devotion. I know his favorite movie, favorite candy, they way he smiles at certain things, or the way his eyes light up when he's talking about something he's passionate about. I know the various secrets he won't share with others or the things that have been so far repressed as to only appear in the little things he does or doesn't do.
What I'm saying is. Him giving people sex is as trivial and as meaningless as him greeting someone off the street with a curt hello.
Having sex with someone does not invite them into your life, your passions, your desires (aside from the carnal) and it doesn't give them a one way ticket to your heart. Sex and romance are not mutually exclusive you can have one or the other or you can have both together, it depends on you and the person of your affections.
tl;dr: If the guy I'm dating trusts me enough to ask me if I'd be okay with an open relationship, then I will sure as shit say yes. Because one, they asked for my consent in the matter, which means they obviously care for me and my feelings; two, I more than likely don't satisfy them sexually and that's okay because I know personally that I won't (I'll repeat it: I'm asexual, I don't have the desire to have sex); three, I'll know where their heart lies regardless of where their dick goes; four, he'll know if he doesn't use protection, I'm going to rip that dick off with my bare hands and feed it to sharks.
You and your guy obviously have a good thing going. And, though you say you aren't ready for commitment, it very much seems to me that you're already both very committed to each other and very devoted to each other, as well. If it works it works? If it doesn't, that's just because one or both of you just can't do it long term. It doesn't mean that these relationships can't and won't work, it just means it's not a fit for you or him or both personally.
And if you ever doubt anything or if he ever doubts anything, that's normal. That's okay. Everyone's going to hit a bump once in a while. Someone's going to get too jealous or someone's not going to feel they're adequate enough for the other. During those points, you may just want to slow down, find each other again and make sure you're both on the same page before you go at it with another person once more. Of course, take my advice with a grain of salt because you'll need to find what'll work for yourself on your own. I'm a stranger. I don't know you personally, so my advice is just something to contemplate and try out. If it doesn't work, it just means you work differently.
It's not cheating if everyone has consented prior. Why? Because they consented. Just like it's not rape if both parties have consented to have sex with each other. It's as simple as tea.
Also, I would like to add that love is not finite. I and anyone else in this world can give love freely and will 100% not run out of it, regardless of personality and view of the world.
Also, if you needed more examples listen to Someone New by Hozier. It's more of an aromantic song but it explains the concept well enough that you can understand the sexuality and people who identify as such much better.
