Assalamualaikum warahamatullahi wabarakatuh.
Have you heard a quote that sounds like this before; "Don't take others for granted. We usually don't know what we have until we lose it."
When someone is being good and super nice to you and always be the one who gives up when you guys fight or misunderstand, s/he always apologise first even if the fight isn't because of her/him in the first place, that means s/he is really taking good care of the relationship you guys have. Some people take this for granted especially when you're the only one who fight for everything while the other side doesn't do anything.
They don't really care or in other words, they hardly feel any guilt or anything and you're the one who always try to mend things up back, as usual. And sometimes they're kinda 'rejecting' your apology even though it's not your fault hundred percent. It's even harder when you're the one who always feel guilty. I have this kind of problem. I tend to feel guilty even in the simple, small petty things which people usually don't care bout it, not to mention greater things than that. Sampai ada orang cakap, "Alaaa benda macam tu tak payah kisah. Buat bodoh je." And I have a friend who has this kind of characteristic, the same as me. Maybe we expect that they would do the same thing, and that's why at the end if it still isn't okay then we're the one who tend to get hurt.
I once did this to someone. She did the same thing to me. After 5 years of being best friends since in standard 1, we fought when we were in standard 6. We didn't talk to each other for about a month! It's all because of a book that I borrowed from her, but she forgot that I already asked her. It was a big fight, I tell ya. Although we didn't talk to each other, I kinda missed her. I felt a bit lost. Then after a month, we apologised and forgave each other. Both of us wanted to apologise, but because of ego, we did not do that until a peak point where we felt like we had no one to talk about stupid stuffs and share little secrets anymore. The best part is, we're still best friends and she's the best-est friend that I have since standard 1 :)
So, actually even though you always feel guilty and always be the one who apologises first, it's okay. But if they always pretend like you aren't there in their life, let them be. As long as you don't do any wrong things, then you'll be fine. Plus, apologising and forgiving doesn't lower you down, and apologising doesn't mean you're wrong.
Here are some ayahs from Al-Quran;
So as a conclusion, don't get tired of apologising and forgiving because it's a noble thing to do. And don't take anyone for granted because if they're not here one day, then you'll feel the lost.