It can be - especially for men - but is hard. I know for me that whereas I sometimes think I'm up for a nsa relationship, it all too often has ended up causing me heartache. I have managed it - once very successfully and for quite a long time - but think it depends very much on your general state of mind and what else you have going on in your life.
When I was seeing Craig, I was very busy with work, was seeing someone else at same time who lived in another city so wasn't up for a full-on relationship anyway and was well aware that I wouldn't want him as a boyfriend anyway .... but as someone to go home with occasionally and have a laugh and a shag with - fantastic!
Think you have to be really aware of your - and their - emotional needs and wants. Not sure any of this really helps but hope you're feeling better - or that I've bored you to booze!