Would you stay in a relationship you know won’t lead to marriage? Please read

Been with my boyfriend 5 years now. We have a 10 month old son. He has two kids 7 and 11. One lives with us full time the other on weekends. I pay almost all the bills. He only pays $300 for rent. Our rent is $1450, plus utilities plus electric. I pay all credit cards (mine but they’re used for us and his kids), car payment and insurance, everything. I love him but he’s so grumpy all the time, constantly cussing and flipping out on people. My mom said recently she dosnt see this relationship heading towards marriage like I want. She’s right. He’s stable, and content. I guess I’m happy right now, but this isn’t the life I want. I want a partner. Opinions?