I'm so dumb!

Please no bashing! I just found out I'm pregnant not sure how far along I am. On Feb 14 we saw a yolk sac and gestational sac. It was measuring 5 weeks and 6 days. I don't have another uktrasound till Monday. Where then I'll have an actual due date. Any who I'm married been separate from my husband since may 2016. He was dating someone I was. We do have 4 kids together. Well I went to visit him from Jan 6 to the 11th of jan. We had s se like every day 3 times a day. The other guy I was on a break with. Well I left the 11 cause my husband and I decided time for divorce and went back to him was having sex with him every day. Well I found out Feb 3 I was pregnant my hcg was 51. I never had a period due to me having a d $c dec 13. And the 12 to 14 of jan I had light pink spotting with brown. Very light though then nothing after. My question is when do you think I got pregnant based off of the yolk sac and gestational sac. I'm so upset. I made a dumb desicion. Just need to know when do you guys think I ovulated and got pregnant with my soon to be ex husband or my boyfriend that I got back with.