why is finding love so hard??

why is finding love so hard??im a 27 yr old m and every girl I’ve been out with has been nice to me for the first weeks then they turn nasty and controlling towards me,im a nice lad to b with and always nice to everyone I like being loving and compassionate in relationships but its the complete opposite with partners.everyone I know in my family have settled down or had kids,got married the full package ,but im still left on my own wondering whats wrong,I go out every week to clubs im muscly exercise often I just dont understand why when as soon as I go on dancefloors im avoided like the plauge.I just watch cocky lads that go around beating people up gettin any girl they want instantly ,maybe theyre just airheads?