In my current story, the conflicts are fairly obvious: my protagonist is offered the choice to either change his past or secure his future success. His first conflict is whether he believes that either is possible (or whether he listens to his best friend, who maintains that the offer has been made by a conman). Then he has to decide whether either choice is ethical. Then he has to make the choice, and face the consequences. And so on.
That's all very well for a horror story. Actions have repercussions, and each new conflict comes as a direct consequence of the decision made in response to the one before. However, it all gets a lot more complex in romance.
I'm trying to plot out a contemporary category romance. I've pretty much got a handle on my main characters now, and I just need to figure out what's going to keep them apart (emotionally at least for much of the story).
Initially there's the whole problem that she's a) his boss and b) his landlord, but that only works until their first physical encounter. After which I need to focus on their individual issues. So...
She hasn't been involved with anyone since her husband died (mostly due to his own stupidity, but she does have the guilt issues connected with the fact that he might have stayed at home and not got himself killed if they hadn't argued that day). So she's not keen to introduce her little girl to someone who might not stick around, especially since husband was a bit of a flake, but infinitely better than the men she'd been involved with before him. On the plus side new bloke does seem good at using his initiative and pulling his weight in spite of being young and therefore (presumably) a bit flighty, But new bloke isn't pushing to get more involved in her life, so she's not going to start assuming that he wants a proper relationship.
He is still smarting from having been dumped by his gf-from-uni who promptly moved in with someone else after never wanting to live with him. He wants kids, but not yet, and really knows far more about how to cope with babies (from email and phone conversations with his big sister) than with older children. Plus his big brother was involved with a woman who had a child already and now they've split up, she's disappeared with both that child and big brother's baby (here Our Hero conveniently overlooks the fact that his big brother has always been a colossal flake anyway). And if she doesn't want him popping round except when her daughter's off with Granny then how's he ever going to find out whether he'll be any good as a stepdad?
In amongst this we do, of course have orphan kittens, serious childhood illnesses and the reappearance of the remorseful ex-gf.
So how much do I need to drag my characters through the mill anyway? Not traumatising them is no fun at all, but there's definitely a tipping point when all that angst becomes just too much.