Mixed emotions ! Help

This is a tough question kind of and I think I already know what kind of answers y’all will give me but I’ve been in a relationship for around a year and a half and I love him so much but we’ve been through so much together ( not cheating though) but lately over the past months it’s just been so tough and for certain reasons and my mental health, I find myself questioning whether I should leave or not , but it’s like when we’re happy , it’s really good but when it’s bad it’s not too good. But now I just find myself thinking of the things I use to could do and people of the past and should I feel bad about it? Should I leave? Is it because of anxieties that he might break up with me soon? I don’t know but sometimes I think that I’m just wasting months if I’m going to keep worrying if there’s someone else or if I should leave . I use to be madly in love and didn’t think of anything or anyone but him . But There’s some stuff that he does that he doesn’t know I know but I don’t like but I don’t mention it but if it’s something with me, he makes it one big issue every single time and I think the main thing is, he disregards my mental health and thinks what I’m going through isn’t really anything serious . Please send yalls opinions though!! My birthday is coming up though and he’s started getting gifts and his mother has been shopping for me too though so I’ll feel bad if I left :(