Ex wants to leave his PREGNANT GF for me

Hi everyone,

I was dating this guy and honestly he liked me way more than I did him & he promised me the world & well I kinda was sacred to enter a committed relationship because I was wanted to make sure he was right for me. Well he loved me & he kinda moved on while I still dated other people. Well he started seeing someone which I was fine with he promised me Valentine’s Day gifts etc even though he had a newly girlfriend. Well things changed as of last night when he told me he got her pregnant 😳 I’m like how far along is she...she’s due in 3 MONTHS! Well now I’m kinda of going through a hard time because of finances well he told me he would leave her if I said I was ready to be serious and committed and married. I’m just like no u can’t because u made that choice ...but I’m ready for a serious committed relationship but now he has someone pregnant ....I know if I said right now I’m ready to be serious he would leave her...should I just back off even tho I’m having a hard time financially and he would literally let me live with him...or just let it go?