Hi there,
It's pretty hard to say based on little information provided, however, what is it that's making the relationship an unhappy one? if it will break her heart does that mean you know that she still loves you?
could it be that you are comparing it to the fun of flirting with this other friend? Which you shouldn't because you shouldn't be doing this in the first place. One, it's dangerous to not only be flirting with someone else whilst in a relationship regardless of how unhappy you are, because instead of focusing on fixing it, your effort goes into this other person where you're finding comfort in. Two, it's dangerous to be flirting with someone who is already in a relationship. Think of it this way, if it was the other way around how would you feel, if you could provide a bit more information, other than saying it's not working or you're unhappy it will be very helpful to get better advice from the fellow netizens on here.
Love is difficult, but we can make it easier to tackle by supporting each other.
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