Because he wants a relationship with no strings attached, a friend he can have fun with without haveing to commit emotionally, because the person he wants to be with emotionally and spend his life with is his fiance but he is not being fulfilled sexually and that is something he souldn't be judged over just because society says he should be.

The reason he probably didn't tell you he was engaged is because he probably thought you would turn him down over that simple fact, and he wanted you to get to know him personally and give him a chance before you made that decision.

He should have been forward with you and given you the option mabe you would't have said no over the fact he was getting married and you would have said no because you are looking for something different than he is. Mabe you are looking for emotional fulfillment and that is something he obviously can't provide.

In short he should have let you make your decision on your own without allowing you to become emotionally invested in him before telling you he can't provide it in return. But people are scared of being denyed

Now to those who bad name this guy because he is engaged and seeks a comitmentless non-emotional fulfillment outside of marrage in my opinion believe in ancient conservative foolishness. Having intercouse with someone outside of marrage is no more different than someone sticking there finger up somone elses nose because it feels good. You should learn to be a little more open mided and not let society dictate to you what is and isn't acceptable. Marrage in my opinion is an ancient trite ritual invented by savages however I do not go around telling people they are bad and fools for believing otherwise. It is time we acted like we have evolved and are mature enough to realise that sex is just an animalistic instinct to procreate and has nothing to do with being emotionally commited to one person.