One of you blurts out "I love you" way too early -- and the other person doesn't say it back.
If it's you to him: Dang! It slipped out, and all you got back in return was a tepid "Thank you." Was sexual euphoria to blame or were you just being honest?
It's best not to overemphasize the awkward moment with apologies or discussions -- let him think it through until he is ready to return the sentiment. And don't beat yourself up. Being open and vulnerable is part of being in a relationship.
If it's him to you: On the other hand, if he opens up to you and you don't feel the same way, be kind and gentle. Make sure he knows that you appreciate what he said and that it makes you feel good. If he pressures you to respond in kind, tell him, "I care about you and I take those words seriously. I'm just not ready to say them yet." You can also just dive in for a distractingly passionate kiss -- beats a change in subject.
Why is it that whenever you start having sex with someone, you stop falling in love with him?
This probably means that the challenge of "landing" someone is hotter to you than the actual potential relationship. Slow down on the sex and work on the emotional side of things first. Don't start messing around until you feel a true connection with the person. Once you have that, the sex will just be the cherry on top (sorry, bad pun).
You need to call it off with someone you're dating but you still want to be friends -- really.
Tired old lines like "Let's just be friends" or "I value our friendship too much to have a relationship with you" have long been fallbacks for cowards looking to duck out of dating someone. Therefore, in the cases where you actually do want to transition a dude from date to pal, you need to be a bit less clichéd.
Let him know that you really enjoy spending time with him -- and cite examples, like your shared sense of humor or mutual love of science museums, before lowering the boom. Tell him that you don't think you are right for each other romantically, and follow up with a platonic invite, like "My friends and I are going to that show we talked about, if you want to join us." You may not get to eat your cake and have it, too -- you have, after all, bruised his ego. But if you continue to show genuine interest in him and are careful not to blur the lines (by letting him spring for movie tickets or indulging in a little "harmless" cuddling, for instance), you guys will be Jerry and Elaine in no time.
He has way more money than you and is always paying for things. You want to reciprocate, but you just can't afford it.
Tell him you are going to take him out for a special date, and plan an evening in your price range. Whether you take him out for Thai or to a kiddie arcade, he'll appreciate the effort.
Another option is to offer to pay for the cheaper part of an evening out -- he pays for the four-course meal (and two bottles of wine), and you pay for dessert. But it's up to you -- if he's loaded, the fact that he's footing the bills most of the time means far less to him than it does to you. It's most likely that he enjoys being the high roller with a pretty lady on his arm.
You'd love to have more sticky situations in love, but frankly, you have no idea where or how to meet guys!