Being Trans in a relationship can be one of our greatest challenges. Sadly, most relationships don't survive, but some do. From the many I have observed, the survivors are truly fortunate, and very special people. The issues often cited are a loss of trust, not what they signed up for, family pressures, and public perception.
Where the couple has been in a relationship for some time, and one comes out as trans, the other will naturally think they have been deceived, and trust is lost. This is why it is important to be open with your partner, and if you are just now figuring it out, involve your partner in your quest. Yes, I know it seems scary telling your partner you may not be who they thought you were, but once trust is gone, it is very hard to recover.
Couple commit to each other, but also for a future life. Finding that future is not what was imagined can end a relationship. Some people simply don't have the ability to accept change, while some may. Working through the realisation of gender incongruence, and the possible consequences, together, may aid acceptance.
Many people need the connection to family, and if family is not accepting, it can put pressure on the relationship. It is important to recognise this, and make every effort to bring family along on this journey. Make sure you understand what is happening, and educate others. There is no guarantee of success, but you can improve your chances.
Couples in a stereotypical hetero relationship may find themselves both re assessing their sexuality if one even only partly transitions. They will realise that those outside their relationship might have similar questions, and this can be very unsettling for many. Where they might be able to cope with having feelings for a partner who is changing appearance, they may not be able to cope with others seeing them as gay. This is a tough one, as trans people who transition well may give the outward impression that they are in a same sex relationship.
Honesty, early sharing, open discussion, and mostly, making your partner a partner in your gender journey as well as your life, are the keys to improving your chances of retaining a partnership. But to be honest, success rates are not great.
Hugs,
Allie