Unhappy, in love

Relationships ebb and flow naturally, but how long should you stay in a relationship that you're not totally happy with in hopes that you'll feel better about it? Idk if I'm just feeling meh about it right now or if it's a more serious issue. We've been dating for a year and a half and I just can't handle how self absorbed he is. He doesn't seem to care about how I experience our relationship :( and talking hasn't seemed to help.