No one loves a love triangle. Just ask Twilight and The Hunger Games. Okay, maybe that was a poor example. For 15 year old me, that angsty YA trash absolutely slapped.

But in general, it's 2019. That's no place for cheating. Certainly not if the guy went ahead and fell for both of you. They think they're being grown up and mature by communicating that to you. Somehow, I think that they forfeited the right to maturity credit when they stopped being faithful. Monogamy isn't for everyone, in fairness – but that has to be discussed.

You don't get to just decide the terms of the relationship.

They are flexible and can be renegotiated if appropriate. But that's not one person's port of call. It's a two way street, as ever.

We need to be better at recognizing that we deserve better than what we sometimes get. Often, we might be investing more in ourselves and putting our time on the line for a relationship that isn't being reciprocated in the same way. Also, we often feel guilt for thinking about stepping away from such relationships, as though we are withdrawing a service that we 'owe' another person. We don't owe people anything in this world, not inherently. Not if they're not giving us the same in return, it's just not emotionally sustainable. You end up expending and exhausting yourself and having nothing left for yourself.

Therefore, we need to recognize and relearn our power to say 'no'.

And mean it. Or to tell the people around us what we need when we need it. We don't need to become dictators or totalitarians to do this or to control the relationship. We just need to have an active and equal part in it. If we want to know where the relationship is headed, that's entirely within our rights. Should your partner not be on the same page as you, that's fine – but that's the signal to leave the relationship. If you explicitly do not have a future there, then you're both wasting each other's time and effort and making things harder for yourself in the long term.

You aren't selfish for leaving a relationship, even if there are other parties involved. Your life shouldn't always be on hold just because there are children involved, or friends, or a contentious situation. If you're unhappy, you have to start to work on that straight away. Children of divorced parents aren't unilaterally worse off than those whose parents stayed together. Wouldn't you rather your parents were happy, even if that wasn't with each other anymore? How is living in a house with constant fighting or tension preferable to a more open, communicative environment? It's not.

In fact, the fact that we still discuss this moral burden of the person who is the victim of cheating, rather than the implications for the cheater themselves, is outrageous.

If they can't make their decision – make it for them.

Not even an ultimatum. It's just not worth the relationship if one party has so royally screwed up and still can't make their mind up. It's a nonstarter.

The right guy – who will treat you the way you deserve – is out there for you. There's no reason you should pressure yourself or push for what you aren't ready for. Don't worry about what other people are doing around you – they don't matter. Seriously, it's your life that you need to live – not theirs. You can't judge your success on their terms or constantly be comparing yourself to them because then you can never win.

But back to the matter at hand. Relationships.

I'm not saying that soulmates are a provable thing or that fate exists in the way that we hope it does. However, I firmly believe that too many women believe in that trashy quote from The Perks of Being a Wallflower. You accept the love you think you deserve.

Don't stick with this one just because you think he might be the 'only one'.

That's nonsense. And – honestly, you aren't even the only one as far as they're concerned.

It's the harsh truth. But you have to get out of that situation and get out fast.