Are some things really better left unsaid?

So theres this guy thats lives like 3 doors down from me in an apt complex im friends with him his sis n his bro are families are close. Its always been on and off again friendship with me and him like never to much but like sometimes well talk sometimes well just by pass each other and we hung out one time last year and it caused a little problems wit his girl cause he was tryna get with me kinda so we havent talked much since then, now his gf is really prego like bout to pop anyday and anyways the other day we started hanging out again and then the night after that i had a party at my house and we was flirting n **** and then he was acting like he liked me and he went out on the back porch and i came back inside and someone went lookin for him and he was gone so i went over to his house and went up and he was layin in bed so i was like why didnt u tell me u were leavin he said cause i knew youd come after me so anyways we came back to my house got talkin and he was like would u be mad if i stayed here without doing anything im like no id respect u even more so we came up into my room and i was layin on his chest and we were talking n hes sayin like he loves his baby ma 100% no doubt about it but **** just aint coshure with them anymore and every since i moved here hes like me but i always brushed it off like hed never have a chance and then hes like i dont know theres just something about you that i like about you. so anyways we fell asleep together woke up and things were still good, he had to go to work so he left and i was going crazy all day confused like hes got a girl whos bout to have his kid n if he does this to her then he would do it to me and i dont know i really like him but she ended up going to his sisters house (where he lives) bout 7:30 that night and he came home about 11pm that night and came over to my house cause his bro n sis were here and i was like get out go and hes like really why u being mean to me (well first off he told me hed be back to MY house later not with his baby ma) so i was kinda frustrated i know that sounds bad but w.e so a few minutes after i went over to his house to give his sis something n he came outside and was like dont be mad at me well talk more and im like no im good i dont want to talk to you and hes like really seriously i said ya im good so then later on he came back over and his sis was giviin him attitude and hes like yo whys everyone givin me attitude im just gonna leave i was like dont play people and they wouldnt give u attitude and he stops and was like really amber thats how its gonna be i said really you made it that way & now he wont even talk to me, so w.e i dont care but the thing is his baby ma is SOOO nice to me and it kills me, ive been in her shoes and this poor girl has NO clue wtfs going on. should i tell her or just forget about it and keep **** civil!