Struggling with a toxic friendship

I (29M) can sometimes overreact when a close friend of mine (28F) go for long without talking or seing each other. We were romantically involved for a while but that was more than a year ago and we talked over why we could not be more than friends and we tried to not talk at all but both of us agrees that they want the others presence in their life even if just as a friend, the problem is that we both have our mental health issues that make her need to isolate and not talk to anyone frequently while for me going for long perios without us talking or seing each other makes me feel like i'm being treated like some accessory that she can wear whenever she wants and then forget about, I told her how that makes me feel and we had many arguments over this and I just feel if she truly values my presence in her life and cares about she can atleast try to make this aspect of our friendship i'm struggling with easier for me. So am I being too insecure/demanding or should she be a better friend and prove that she values my friendship?