Hi just need an opinion

My boyfriend and I️ been together going on 4 years next month he tells me for the last two years he’s gonna propose and every time he says he gonna do it he makes and excuse of why he needs more time I️ love him to death but anytime we go thru something he’s flirting with girls in they inboxes on Facebook and he tells me he’s sorry and he don’t want nobody but me I’ve had three miscarriages and I️ really want a baby he says he would give me one but than he changes his mind about that also I️ don’t want to throw away 4 years because I️ love this man we got six 6 between us I️ have 2 girls and he has 4 girls and he’s been with my youngest since I️ was pregnant so to her that’s her day I️ don’t know what do