Hey Emily, how are you? I hope you're doing just fine!
As a non-native speaker, I shall not be able to provide you with perfect answers to all of your questions. However, I may help you by giving you some hints!
1) I think the word ''suffocated'' should befit your context quite perfectly. Also, you could rewrite it as: ''I felt both pampered and [suffocated] [by] being in love with him'' or ''I felt both pampered and [suffocated] [by] his love.''
2) In this case, you might want to replace ''each other'' for ''one another'', as they have the same meaning. So, you can say: ''I like the way my friend Helen and her boyfriend love each other. They trust one another, care about one another, and think that each is "the one'' (or ''... and regard each other as the one.'').
3) In this case, you can say either 'fulfilled dreams' (if they have already been achieved), or 'dreams to fulfil' (if they are to be achieved one day):
Example 1: ''I think this is how a healthy love should be, feeling happy from the heart for your partner's fulfilled dreams, rather than feeling threatened by them.''
Example 2: ''I think this is how a healthy love should be, feeling happy from the heart for your partner's dreams to fulfil, rather than feeling threatened by them."
Hope that helps! :)