Stuck in repetitive toxic dating pattern

Guys, I am reaching out to you because I have made a mess out of my dating life.. I am quite an insecure person when it comes to people staying in my life.. I am trying to grow out of my people pleasing tendencies but I am unable to address them on time when it comes to dating.. I have been craving a fulfilling romantic relationship for years now. The problem is that when I come close to dating someone I put off my needs for too long and try to understand the other person.. Due to this, when my threshold has reached I realize my emotional needs are not being met.. I don't know why I do this everytime.. I start to romanticise the possibilities when I am in the initial talking phase and when the reality hits me it's brutal..

I try to be adamant that I won't do it the next time but somehow I convince myself to do otherwise.. I make myself extremely miserable and the other person remains clueless when I suddenly start to express my needs... And unfortunately due to this, I have never been in a real relationship.. I feel like I am a toxic person who only creates chaos when it comes to a romantic relationship.. When I am in the zone of getting to know someone, I even ignore the valid advice and warnings given by my known ones.. Now, I am really sick of my behaviour and really wish to break out of it.. Please help me, what can I do??