Sleeping with someone while going through a divorce

I'm sleeping with someone I use to be friends with in high school while going through a divorce. It has been about 7 months now. It's been mostly sexual since it's been several years since we've reconnected but here and there he reminds me of the who he use to be and I'll falling for him. He doesnt want to be in a relationship and I know I cant handle one as a single mom but even time I leave from having an amazing night with him hes distant and barely talks to me for a few days. I know I should stop seeing him, hes not that into me, and if hes unsure now he will never be sure if he wants me or not. I just cant stop seeing him ( maybe once or twice a month when my son is with his dad). I mostly need to just let the secret out. Why do I feel so much for someone that doesnt feel the same about me?