My bf stated he's only with me for the kids but loves me?

So ill try to make a LONG story short. Yesterday me & my bf got into a fight , about him not wanting to go to the store to buy formula. He usually isnt this way but he is stressed i guess about being late on bills so lately when i ask for things i get attitude. whatever.

We barely get into fights ... But when we do he always threatens our relationship. says i need to change my attitide or he cant be with me .. ONLY WHEN WE FIGHT THO HE PULLS THIS. maybe he does feel that way . I dont even see the attitude just when i ask him to do things around the house & he doesn't i get snarky. we have a 2 month old & an 18 month old btw. and yesterday during this small fight he says i need to change my attitude or he cant be with me and its starting to feel like he is only with me. for the kids. he claims he loves me. but i told him if he is not happy then leave. We have been happy . going on vacations to family house . having great sex now that we can ...i thought things were going well . telling me how he wanta to marry me but when he gets upset he is ready to throw in the towel. this hurts my heart. i feel betrayed that its like he is lying to my face. he says he inagines me in 20 years with this same attitude problem.. honestly its not something i can fix. . i have two small kids and are stressed out most of the time. .. I wish he would be more appreciative and help out but its like pulling teeth. he will eventually do it but he waits for me to get the attitude. its a cycle. . i cant break it alone and i told him this. . im more upset that ive felt LOVE & like we have been good & now i feel played as hell. i broke up with him because i told him i cant walk on eggshells waiting for you to lose your patience with me. if u are unhappy then leave dont stay here because you are comfortable or your waiting for a major change because it wont happen. ... i wrote him a letter last night expressing my feelings of why i cant see us staying together. ... THEN HE GETS INTO A CAR ACCIDENT THIS MORNING. i wasnt gonna talk to him but now i feel suckered in because its like a reality check. he is ok. his car is not. But he wont confront me and i dont want to confront him because everything he says about our relationship hurts my feelings. ... what do i do now? i told him since he is on the lease legally he dont have to leave yet but we are separated and i slept downstairs. he is trying to watch a tv show with me acting nonchalant but i cant help but to sit here feeling like crap like he dont love me. if he did he would try harder to make things work. i need some REAL advice...