Should I leave him

I just discovered my boyfriend of 4 months still has his dating app and talking to other women. I am sure nothing has happened yet. He is constantly telling me he wants marriage and loves me and that I am his whole world. He spends lots of time with me almost to the point of suffocation. There are some other red flags too. My dilemma is if I leave it leaves him and his mom (who is an absolute sweetheart) stranded and alone with no one to help them they don’t have a vehicle and he has no license. He has no other family willing to help with him getting to and from work his Dr appointments and such. He is my first try on having a relationship after my 20+year marriage ended with my husband leaving me for another woman leaving me homeless and over 300 miles from any friends or family that could help me. I do want out but how can I leave someone in a situation that I have been in and understand how hard it will be.