I am not getting any younger

Good day house, please I need advice on this; I'm completely new to dating. I never thought people were this dirty in real life. I don't go out a lot hence making it hard to meet people. I result to online dating. I use Facebook and 2go. Met a few people on 2go. The first guy from 2go was nice and very eager. I actually drove to him from Ibadan to Akure, a straight 4 hours journey and on getting there. I found out he was a Yahoo boy. I was so angry but the 2 days I was there, I acted like I wasn't really bothered and I just observed what he was doing so as not to make him get mad at me because he seemed like the violent type. Even though he said he REALLY liked me, after I left the 3rd day like this, I deleted his number from my phone and drove him away. Next, I got my first Boyfriend from Facebook Messenger. He was an absolute mess. An alcoholic, smoker, gambler with anger issues. Always puts me down.. dumped me twice and almost cheated on me. Again I didn't have a lot of money but I took care of him. Took a break for 3 months and went back on to online dating. Recently met this engineer from Facebook Messenger still, He graduated from a nice University. Doesn't party or drink. I thought oh wow, he's different. I usually attract party boys so maybe he's decent. We were supposed to hangout but he stood me up not once but twice. I felt humiliated and cried on my way home. I didn't have a lot of money and I sacrificed that as well. I feel like nothing. I tolerated their lifestyles because I didn't want to be picky but they all end up leaving me. Everyone I meet dumps me, rejects me or stands me up. The attraction isn't bad hence we match off our pictures. I dont know what I'm doing wrong. Like I said it's so hard for me to meet people so I result to online dating. I also seem to put the most effort into everything and always drive to the guys but they never do so for me. I look around and girls I know who have multiple bfs or messing with different guys end up in relationships. I'm being genuine and they all just leave me hanging or don't bother messing with me at all. Please what do I do? How can I meet the right guys? I am 27 years now, I am not getting any younger.