Thank you for writing. I’m sure you understand why he’s upset. From his point of view, your personal troubles have suddenly caused a major change in your relationship. He thought he was involved with a partner who is sexually attracted to him and who is excited to share sexual intimacy. It’s a reflection of his love for you and his attempt to be understanding that he hasn’t left you over this sudden change in your partnership.
You are absolutely right that the difference in your sexual desire is putting pressure on your relationship. The scoliosis has always been there so something else has caused the change in you.
I have to wonder if your depression and the drugs you are taking are what is making you “okay” with a low libido. SSRIs (Selective Serotonin Reuptake Inhibitors) that are commonly used for depression often cause a drop in sex drive. In fact, some studies have shown that as many as 50% of users of SSRIs suffer a major drop in their libido. I hope you will talk to your prescriber about whether some changes can be made in your medication (either the medication or the dosage or even the timing of when you take it) so you can reclaim that part of yourself.
A low sex drive is treatable. But you need to find a qualified couples therapist to work with. Ask your doctor for a referral to a local licensed couples therapist who works well with sexual and intimacy problems. The therapist will help you address your self-esteem problems and will help your partner learn ways to support you as you deal with them. A couples therapist can also provide a safe place to look at whether there is an underlying problem that has caused the two of you to be engaged for 4 years instead of marrying. It could be that the sexual problems are an outcome of something amiss in your relationship that the two of you either haven’t identified or have been too scared to address directly.
A crisis in a relationship can destroy it or be an important point of self-discovery and growth. You and your fiance have been together for four years. I hope you will give therapy a chance before you throw away a relationship that has been meaningful to you both until a year ago.
I wish you well.