I just don't know anymore?

im 19 and have been in a relationship with with a 17 y/o girl for about two years. she had a bad childhood, father dieing at 5, being beaten by step dad for a year. mom is somewhat and alcoholic. not a horrible childhood but had to have some psychological influence. while young around 13-16 she went out with several guys. she told me that she only kissed them and that was it and had oral sex once with one. however psychologically she liked each one, even tho she barely knew them. she seems to fall in "love" very quickly, and by love i mean infatuated or lusting. or she might see males a sense of security as she never had a father so she uses them for a form of protection against loneliness or maybe as guidance. she tells me she loves me, she is loyal as can be but is it just because i give her security. as she grows i believe her insecurity will fade making her more confident and in turn making me less essential to her life. she says she loves me now but will she love me then or will she just seek the better outcome leaving me for another male. time will tell. if this does happen then there must be no way to know if love is real or not. ****, is love even ever real or is it just a complex mechanism by brain chemistry to fool ourselves into reproducing. then are we just always seeking for ourselves even when we say we care for others? i mean even if i give money to the poor im not only doing it because if have sympathy, im doing it because it makes me feel good for doing good. is it even possible to become completely altruistic. why do i always feel alone.why do most women just feel and not think. the woman im with never talks to me, she just listens to me talk about what she says to be "deep subjects". does she actually understand what i say, she says yes but i doubt it because no1 i have ever met understands my perspectives. if she doesn't understand does she at least care about what im saying or is it only my voice and it's projected direction towards her giving her a sense of attention. i doubt her because i know a few men who can deeply philosophize but why no women, i even met around the same number of each gender but still i remain abject. i know what my woman wants, she hints and even tells me it. she wants me to say that i love her but how can i love someone back when i have so much doubt in human values? do i get over it and force myself to conform being quick and certain with decisions despite the high probability that they will be reckless and lead to sadness. or do i regret whatever i do either way. **** life, were all dumb and unknowing. the worst people are the ones who think they're right and everyone else is wrong. ironically those people are all people.