Sort of a LONG ASS POST!!!! I’m just ranting and asking questions I mainly just needed this out of my system BUT I still need advice........

Let me say that me and my husband have been separated for 2 months now we’re getting a divorce! I’ve been this guy friend that’s my best friend and on the 29th we had sex I’m pretty certain I ovulated August 8th or 9th because both days had egg white CM on the 9th I had heavy egg white CM today me and my husband was at our home together and well it happened multiple times it was a moment of weakness thinking he was different and changed so I let my mind slip away!!! I’m scared since I was so close to ovulation having sex with him because I have PCOS and never really can tell when I’m ovulating this month was the first time it’s was a lot of egg white cm... what I’m asking is will I be ok? Also do you think I should get plan B??? I don’t even know what I was thinking please don’t judge me for this mistake I made I understand I feel more hurt because my best friend and I agreed on becoming friends with benefits and I just got my STD test back (my husband had an affair) so we both agreed to get tested before we started becoming friends with benefits but I’m certain we’re both catching some type of feelings for each other since we’ve always been close and he’s such an amazing man. But he knows I don’t won’t to rush anything plus I’m not even trying to get in a relationship when I still have a lot of things going on for instance I’m still married and in the process of a divorce I was in a really bad marriage.. with abuse, manipulation, etc. he doesn’t won’t to admit he’s having feelings but I feel and can see I think he does my thing is I feel guilty like I just cheated on a really good guy.. we agreed that doing this friends with benefits we would tell each other when there was someone else or if we have sex with someone else so each other can know (his idea) because I just thought friends with benefits was legit just have sex and go but I guess not! Anyways I feel guilty for sleeping with my husband but I don’t won’t to tell my “friend” because I know he’s going to get upset... also what is your opinion on plan b does it affect your body like bad does it harm you from having kids in the future?