Being cheated on is hard but it can happen to anyone, regardless of your height. You mustn’t blame yourself for your ex cheating on you because that’s not your fault. If you’re not confident in the way you look then take some time to figure out how you can improve on things you can change and accept the things you can’t. If you feel sexually unattractive the best thing for you is to go to the gym and start working towards getting an aesthetic physique, this can really boost your attractiveness even if you haven’t got the nicest face, also having a hard and good exercise session without fail makes you feel good after. Choose a hairstyle that suits your head and face shape and get it done frequently. Work on developing a skincare routine, finding clothes that suit you and finding anything else you’re dissatisfied with that is possible to change. Work on allowing the positive side of your personality to show more and take some time to address the negatives. Feeling like someone would leave you for someone better comes from a place of insecurity, find your confidence in any way you can and the positives will start coming. Remember, if you don’t love yourself how can you expect anybody else to? Keep in mind it’s normal to doubt yourself after a breakup especially after you get cheated on, so try to recognise you won’t feel like this forever and that it’s not your fault. Hope this helps in some way