Problem: A guy has a girlfriend (option A). He isn't sure whether the relationship will last because she hasn't told him how she feels about him. He has an ex-girlfriend (option B). Who he may still be in love with and who has recently told him still has feelings for him. He has also never been single long enough to get over over a relationship (option C).
So I propose an experiment. Clone him. Clone A stays with the girlfriend. Clone B gets back with the ex. Clone C gets single. At the end of the year the clones all get measured on Dave C's happiness scale, and he replaces whichever is happiest. The clones obviously get shot. And one or two girls get heartbroken. Or happy. Depends how it goes. Maybe if the relationship(s) go(es) really badly the girl(s) get(s) to shoot the clones.
Obviously they'd all have to live apart, otherwise the girls and everyone they know would get confused. And all existing friends would not be able to be contacted/or at least could not know about his relationship status. So there may be a few variables. Unless we can find a third place identical to both Swindon and Disneyland Paris. And the second paragraph may make it difficult to get this past an actual ethics committee. But I'm pretty sure shooting your own clone isn't illegal. They don't have birth certificates for clones so they probably can't have death certificates either. And without a death certificate I don't think anyone has legally died. So you could probably kill as many clones as you want. Which is probably why the good guys could wipe out an entire army in Star Wars and still be the good guys. They didn't technically kill anyone because it was an army made of clones. Murdering people not born of woman is fine. Just ask Macbeth. (Yes, we're assuming they're emerging fully-formed from a cloning machine and not made using eggs and grown in a womb. Because then we'd have to wait for them to age and this experiment would be useless and make no sense. Obviously.)
This reminds me of the response I'm working on for when my Gran starts the 'your mother had had you by the time she was your age', 'when are you going to make me a great-grandmother?', 'aren't you pregnant yet?' bit this Christmas. It started with "I can't remember to feed myself. And I am yet to have something really, really important that I haven't lost or at least misplaced for a significant period of time. I have literally never had an umbrella I haven't left somewhere. And killing a child through neglect is illegal, even if it's through sheer incompetence rather than intentional neglect. And I don't think I can finish my Masters if I'm in prison."
However this is where my argument falls down. Yes, I would be kicked off my current Masters course if I get sent to prison for accidentally causing my own child's death by losing it somewhere between my lectures and a pub. But then if I were in prison the government would probably fund another Masters course and a PhD. So really at the moment my best bet to get PhD funding might be to commit accidental infanticide. But then if I have a child because I know I'm incapable of keeping a plant alive for more than 6 weeks and have never managed to keep sea-monkeys for more than a week and therefore it's likely to die and provide me with a free PhD, then it's more intentional accidental infanticide. Which would make me even more of a bad person than the fact that this is actually something that I've properly thought through in my head, even if I'm too scared of having a human being come out of my vagina to actually go through with it. Plus it would completely put an end to my diet. And I want to sort my abs out before I get pregnant in the very, very distant future as it apparently makes it easier to get your figure back, since if you have a core as weak as mine at the start of pregnancy it's essentially going to mess up your muscles and you'll never get decent abs.
Yes, this is the problem with funding my PhD through infanticide; it would completely screw up my abs. I hope to Darwin there's no hell.