Promise rings? (Sorry this is long)

My boyfriend and I have been together for a year & a half. We've been through a lot (in our opinion) because a lot of stuff happened to us throughout our relationship (he went to college, my sister had a very heartbreaking miscarriage, and before he went to college in 2013 when we were friends our school went through a huge tragedy) anyway, he's wanting to get me a promise ring, not a promise to get married so much, but a promise he's going to try hard to be a everything I need and more, and we're always going to promise to work it out.