After some many tries

I found my self single, my two last relationships my exs got the baby mother pregnant, the last one refuse to get out completely from my life , but I decided not to have sex with him for more than two years, but I find my self very interesting in have sex , with people I just know , but I dont want no,serious relationship, I never been like that , and I have a second thought about how I feel, but is what I want to do. And I feel if I get serious I would like to have a man and a woman, at the same time... i feel horrible, for what i want , and i dont know what to do , i just turned 43, I know life is one ,what can I do?