I slept with my married best friend, any advice?

So basically, I've been friends with this girl for about 4 years now. We got super close and it was purely platonic for about 3 years. I had no feelings towards them and as far as I know (cause they told me) she didn't have feelings towards me over those years. Then one night when we were drunk we kissed which wasn't weird it was more of a friendly peck. A week later we had a night out and kissed again but it evolved into a full on make out session. Every now and then, mostly on nights out like that, we would make out. She confessed to me that she was in love with me but also still in love with her husband whom she has 3 kids with. At first, I didn't really feel that way towards her it was just fun making out but I told her I loved her too. I ended up developing real feelings for her and we slept together. We've slept together around 10 times now over the past year and she is still with her husband who she still loves. I dont want to home wreck, and she feels guilty when we do sleep together but we also can't deny that we love each other and are so attracted to one another that we sleep together.

Basically, how wrong am I? I know its not great, but it's just an us thing. Like it makes sense to us that she can love us both but we still feel guilty.

Also, she is still with her husband. They celebrate 10 years together and 3 years of marriage in about 2 months time.

So, what do I do?
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I have ended things.
I slept with my married best friend, any advice?
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