You can help who you fall for. Or do you take no responsability for anything?
Find someone of your own. not saying he's not at fault but why do you want someone that that is attached, also those lines he gave you are the oldest lines in the book.
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I actually don't agree with the first sentence. You don't 'choose' to fall for someone. It's like chickenpox - it just happens and takes you by surprise. Of course you can chose to act on it or not, but I really don't think attraction is a 'choice' at all.
It's not as though you can go along with a tick-box - age correct, unattached correct, income correct, ethnicity correct and so on.
Heck, you can't even 'chose' which gender you might be attracted to or indeed when.
Marriage is a largely artificial institution which was started when people lived far shorter lives and in any event it was never designed to have much to do with 'being in love' or 'falling' for someone. It was designed for practical, social and economic reasons. Nothing wrong with that but if you go back to the origins of romantic love it was nothing to do with marriage.
I digress. But the idea that you are attracted to someone just because they are your age, or just because they look right on paper or just because they are single is silly.
Having said that OP, you sound miserable and I think detachment from the drama triangle would really help you. Date other people and try to have fun. Men are perverse, imo, when you disappear they want you more and when you are available they then disappear.
I think that's why so many men have affairs - the above peversity.