PREGNANCY

I know this isn't really relevant but I need about the smallest possible advice I can receive. So me and my significant other have been trying to conceive for almost about a year and a few months now. I have not been able to conceive and I believe it's because of me receiving depo provera in the past. So anyways my significant other has a cousin who I extremely adore and love (I baptized her child) her (child's father boyfriend) has a sister who I cannot ultimately stand because she has gone to the fullest length and extent to grab my significant others attention. Before me and him were in a relationship, him and her would secretly hook up behind his family's back and his cousins back as well. She would claim she was sleeping over her sister is laws house (the one who I love and adore) but she would sneak out and walk to my significant others house to sleep with him (they're neighbors) the sister who tried or did hook up with my man is still around so I have to see her. Every time I see her my skin crawls because she does things for attention. Not only to seek my mans attention but mine as well to let it be known, she also has a boyfriend but does not care because she cheats on him ( as I was told) I have been on my journey of trying to conceive as i found out two months ago she purposely miscarried because she didn't want a child. She has had a few abortions and a few miscarriages and guess what guy? SHE'S NOW FUCKEN PREGNANT, and she now has came to her senses and decided to keep the baby. I am so upset and sad I have been thinking about this all night, she was here at my significant others house because his mom has parties frequently so I'm forced to see her, I always keep it cordial so that she knows I am not the problem and have no hate towards her just no respect for her. I nicely congratulated her, but now I want to stop my journey with trying to get pregnant for a few months because I do not want the same or near due date as hers because she would take it intentionally and think other wise as if I am trying to grab the attention which I'm not i've been on a longer journey than her which her pregnancy was not planned .. please I need advice this really bumbed me out, SHOULD I CONTINUE TRYING OR STOP?

P.s excuse me if I mis spelled anything I was typing to fast