It takes a while to repair your relationship after an affair. Do not expect your partner to jump right back in bed with you after an affair even if he or she has forgiven you and forgotten a lot of the transgression. It takes a lot of effort and time, and a lot of times you have to start anew. You have to start from courtship and dating and do romantic things together and slowly build up the sexual tension, the trust.
It also takes a while to repair your own self-esteem. You may internalize things. You may personalize their fear. You may feel you weren't attractive enough, that something's wrong with you, you are somehow defective. "Why wasn't I enough?" is the thought that's common, that's very common of the people who suffered, who were the victims of the affair.
So it's important to deal with your own feelings, to tell yourself that you are a capable, worthy human being, that you're attractive, to do things that make you feel good, that make you feel attractive and desirable. Whether it's going back to the gym, it's going out with your friends, whether it's changing your wardrobe, whatever makes you feel sexy and desirable is also very important.
And of course, it is very important to keep your communication open in an affair, to discuss your own feelings as they may arise again and again. Those feelings of insecurity and hurt. Just because you've moved on, it doesn't mean that those feelings won't resurface. And it is important that your partner reassures you and makes you feel sexy and desirable and wanted. So keeping channels of communications open, making sure that you confide in your partner, making sure that you spend a lot of quality time together is very important to repair and to keeping your relationship strong after an affair.