Is it LUST?

So I had got caught up in a situation, which clearly isn’t the best. I was having sex with two men 1 who I was dating for over 5 years and 2. The other I met at work. I got pregnant the same month when I was having sex with both of them. Anywho the other guy I did meet at work doesn’t want the kid etc.. but it’s too late I kept her and had her and we’ll be doing a dna test soon. (Through the 1st guy) my reason to coming on here is that why am I so attached to the 2nd guy? I reminisce our sex, I think about him all the time, it’s like a deep attachment and I’m just so lost on how I have such a deep attachment to him someone who I was fooling around with for only 6months and had no deep intentions with. Compare to someone I was dating over 5 years! I’m more hurt by the other guy then the 1st! And It’s like I have such a soul tie with the 2nd guy. I can’t explain it but it’s so odd I need advice