Yes I have been that women who had an affair
I was single he was in relationships, not married but living together with her children
I first meet him on my first day at work, his company was the contractor carrying out the big refurb m, he immediately pursued me, nothing physical happened between us at that point as I had just come out of s messy relationship and was pregnant and first I didn't know about her or the children, he then left where I was working as that phase of refurb was over but we kept in touch my text and he asked me to fly out to where he was working abroad to see him, and first I knew about her was when she called me when I was 8 months pregnant, I was shocked and told her I didn't know about her or her children and that other than texts nothing had happened.... I didn't hear anything from either of them again
I went back to work after maternity and he arrived again to start the next phase and again immediately he pursued me, he basically swept me off my feet and promised me the world, he told me he was leaving when XYZ had happened etc he even had me tracking down houses for him to rent in the area, I heard it all how unhappy he was, he didn't love her etc etc
Again she found out and contacted me as per his request I didn't tell her anything (she had evidence of what was going on) and again from that day he never spoke to me again, we had to carry on working together and he basically totally ignored my existence, he also then started to bring her into my work place for lunch, coffe, valentine night meal & room
And last I heard they are now engaged
I'm honestly not proud of what I done and it totally destroyed me, I should of run from the hills the second time he approached me after finding out about her but I didn't and looking back I think I was vulnerable and I truly loved that man
Now 18 months on I'm finally getting my life back on track but the experience has totally broke me, I've tried dating but I now just have no interest I can't see how any man will ever fit into mine and my children's life I guess you can say it's left me a little bitter
I would strongly advise your friend to walk away now before he totally ruins her