Relationship is really getting to me

I've been in a relationship for 4yrs going on 5yrs Aug.11th(8-11-12) and engaged for 3yrs going on 4yrs Dec.26.(10-26-14)I was young when I entered my relationship and things was so rocky/bad he was talking to other girls and sending nudes pictures to them and on the phone late night with them when I use to go home. That been happening all the way until we got engaged(crazy right I should have left) was still doing it kinda up to now. And my fiancé knows I don't trust him but he trust me. And he carry his tablet n phone every where he go but I leaves my phone out in the open, he says he not talking to other girls but I got to a point to where I had enough of that and lost feelings I'm still young and only 22yrs old we don't have no kids together but is trying to have one. He have a different mind set and yes we are still together but I don't know for how long I can't tell th future but for now we are at the stage of TTC a baby! So my question is if I where to get pregnant would my thinking about him change?? Would things still be the same. Do people feel the same way I do like one minute I love him don't wana leave but the next minute when he makes me mad I don't want him no more is this normal at my age😩😩😩 I'm Stressed Out Some one follow me and help me.