If it's too early in the relationship to suggest therapy.....then it's too early in the relationship to KNOW that you are in love with this person.......lust...infatuation yes, but NOT LOVE......love grows with knowing the person & with bonding.

I had issues with the person I married before we got married (Not NPD....but just a few months ago, with research, I have found out what I was dealing with for all those years & what was bothering me even before I stupidly didn't listen to my gut feeling & NOT GET MARRIED)

People NEVER CHANGE......you can almost be guaranteed of that especially if they like the way they are & there is no incentive to change.....& some things like my situation....this person was like that all his life but it was before any diagnostics existed for what was causing the problems in our marriage.

I don't think it's a rule of thumb to RUN FOR YOUR LIFE.....but if there are things about them that ARE BOTHERING YOU before you are in a long term relationship.....it will only get worse. If your gut feeling it telling you that there are serious things going in that you don't like....listen to those gut feelings & call it quits NOW. Gut feelings are always something that NEED TO BE LISTENED TO. I learned the hard way.....& then for a time there felt like there was no escape & my depression got so bad, there were many times I was willing to end my life just to get out......all because I didn't listen to my gut feeling.