It always depends on the concessions being made. If you are giving in on what style of china patterns you like, that is nisht geferlach. If you are giving in on hashkafos that you previously thought were different, i.e. he suddenly wants to be supported, quit his job and learn full time, or vice versa, leave the Yeshivah and work full time, when you had discussed and settled the issue, or he presented as a guy who would never own a TV – because that is your hashkafa – and then insists on one, or vice versa, those are not kleinekeit. If she wants to live ONLY in the USA, and he said that he felt the same way, but then suddenly is only aliyah-minded, or vice versa, these are important issues.
My daughter will not have a pet in her home, especially a dog or cat. She has been redt many shidduchim with guys who want to have or do have a dog. Likewise, she will not date a smoker. So if he gave it up, and then suddenly wants to smoke again, it would be a deal-breaker. And these are not even major issues. being controlling IS a very major issue. If you are making concession on important things (like who gets to control the money and how it is spent), that raises red flags to me.